This PR introduces a new UI element type for Gitea called `flex-item`.
It consists of a horizontal card with a leading, main and trailing part:


![grafik](https://github.com/go-gitea/gitea/assets/47871822/395dd3f3-3906-4481-8f65-be6ac0acbe03)

The idea behind it is that in Gitea UI, we have many cases where we use
this kind of layout, but it is achieved in many different ways:
  - grid layout
  - `.ui.list` with additional hacky flexbox
- `.ui.key.list` - looks to me like a style set originally created for
ssh/gpg key list, was used in many other places
  - `.issue.list` - created for issue cards, used in many other places
  - ...

This new style is based on `.issue.list`, specifically the refactoring
of it done in #25750.

In this PR, the new element is introduced and lots of templates are
being refactored to use that style. This allows to remove a lot of
page-specific css, makes many of the elements responsive or simply
provides a cleaner/better-looking way to present information.

A devtest section with the new style is also available.

<details>
<summary>Screenshots (left: before, right: after)</summary>

![Bildschirmfoto vom 2023-07-09
21-01-21](https://github.com/go-gitea/gitea/assets/47871822/545b7da5-b300-475f-bd6d-b7d836950bb5)
![Bildschirmfoto vom 2023-07-09
21-01-56](https://github.com/go-gitea/gitea/assets/47871822/b6f70415-6795-4f71-a5ea-117d56107ea1)
![Bildschirmfoto vom 2023-07-09
21-02-45](https://github.com/go-gitea/gitea/assets/47871822/47407121-3f2a-4778-8f6d-ad2687c2e7b3)
![Bildschirmfoto vom 2023-07-09
21-03-44](https://github.com/go-gitea/gitea/assets/47871822/76167aaf-c3b2-46f6-9ffd-709f20aa6a34)
![Bildschirmfoto vom 2023-07-09
21-04-52](https://github.com/go-gitea/gitea/assets/47871822/af8fdde5-711e-4524-99cf-fb5d68af85b9)
![Bildschirmfoto vom 2023-07-09
21-05-25](https://github.com/go-gitea/gitea/assets/47871822/ae406946-e3e4-4109-abfe-b3588a07b468)
![Bildschirmfoto vom 2023-07-09
21-06-35](https://github.com/go-gitea/gitea/assets/47871822/2dbacc04-24d6-4f91-9e42-e16d6e4b5f1f)
![Bildschirmfoto vom 2023-07-09
21-09-03](https://github.com/go-gitea/gitea/assets/47871822/d3ca4e56-a72f-4179-adc8-98bfd638025b)
![Bildschirmfoto vom 2023-07-09
21-09-44](https://github.com/go-gitea/gitea/assets/47871822/df1fa689-499c-4e54-b6fb-3b81644b725f)
![Bildschirmfoto vom 2023-07-09
21-10-27](https://github.com/go-gitea/gitea/assets/47871822/b21cac71-a85a-4c8c-bb99-ab90373d8e09)
![Bildschirmfoto vom 2023-07-09
21-11-12](https://github.com/go-gitea/gitea/assets/47871822/89be39cf-0af9-4f2d-9fca-42f9eb5e7824)
![Bildschirmfoto vom 2023-07-09
21-12-01](https://github.com/go-gitea/gitea/assets/47871822/079579ea-1ecb-49c0-b32b-b59ed957caec)
![Bildschirmfoto vom 2023-07-09
21-17-44](https://github.com/go-gitea/gitea/assets/47871822/61ac6ec4-a319-4d5c-9c99-2e02a77295ba)
![Bildschirmfoto vom 2023-07-09
21-18-27](https://github.com/go-gitea/gitea/assets/47871822/5b55b73f-6244-47f7-a3e6-c5e4a7474585)
![Bildschirmfoto vom 2023-07-09
21-19-18](https://github.com/go-gitea/gitea/assets/47871822/c1b7c22e-3e5a-46d4-b8d6-5560db478c0b)
![Bildschirmfoto vom 2023-07-09
21-29-13](https://github.com/go-gitea/gitea/assets/47871822/82ffca8d-ab2e-4a18-9954-5b685bf6a422)
![Bildschirmfoto vom 2023-07-09
21-30-11](https://github.com/go-gitea/gitea/assets/47871822/ad2fdccc-2be8-41bb-bfdc-a084aa387b61)
![Bildschirmfoto vom 2023-07-09
21-32-44](https://github.com/go-gitea/gitea/assets/47871822/2d298ba7-d084-48b5-a139-f86d56262110)
![Bildschirmfoto vom 2023-07-09
21-33-28](https://github.com/go-gitea/gitea/assets/47871822/4cbd838e-9de8-4ad0-8ed9-438da5c9a5cb)


</details>

---------

Co-authored-by: Giteabot <teabot@gitea.io>

This gives more "freshness" to the explore page. So it's not just the
same X users on the explore page by default, now it matches the same
sort as the repos on the explore page.

---------

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

I've heard many reports of users getting scared when they see their own
email address for their own profile, as they believe that the email
field is also visible to other users. Currently, using Incognito mode
or going over the Settings is the only "reasonable" way to verify this
from the perspective of the user.

A locked padlock should be enough to indicate that the email is not
visible to anyone apart from the user and the admins. An unlocked
padlock is used if the email address is only shown to authenticated
users.

Some additional string-related changes in the Settings were introduced
as well to ensure consistency, and the comments in the relevant tests
were improved so as to allow for easier modifications in the future.

---

#### Screenshot (EDIT: Scroll down for more up-to-date screenshots)

***Please remove this section before merging.***


![image](https://user-images.githubusercontent.com/30193966/229572425-909894aa-a7d5-4bf3-92d3-23b1921dcc90.png)

This lock should only appear if the email address is explicitly hidden
using the `Hide Email Address` setting. The change was originally tested
on top of and designed for the Forgejo fork, but I don't expect any
problems to arise from this and I don't think that a
documentation-related change is strictly necessary.

---------

Co-authored-by: silverwind <me@silverwind.io>

- close #22301

workaround for https://github.com/go-chi/chi/issues/781

Always respect the `setting.UI.ShowUserEmail` and `KeepEmailPrivate`
setting.

* It doesn't make sense to show user's own E-mail to themself.
* Always hide the E-mail if KeepEmailPrivate=true, then the user could
know how their profile page looks like for others.
* Revert the `setting.UI.ShowUserEmail` change from #4981 . This setting
is used to control the E-mail display, not only for the user list page.

ps: the incorrect `<div .../>` tag on the profile page has been fixed by
#23748 together, so this PR becomes simpler.

Change all license headers to comply with REUSE specification.

Fix #16132

Co-authored-by: flynnnnnnnnnn <flynnnnnnnnnn@github>
Co-authored-by: John Olheiser <john.olheiser@gmail.com>

* Add initial playwright config

* Simplify Makefile

* Simplify Makefile

* Use correct config files

* Update playwright settings

* Fix package-lock file

* Don't use test logger for e2e tests

* fix frontend lint

* Allow passing TEST_LOGGER variable

* Init postgres database

* use standard gitea env variables

* Update playwright

* update drone

* Move empty env var to commands

* Cleanup

* Move integrations to subfolder

* tests integrations to tests integraton

* Run e2e tests with go test

* Fix linting

* install CI deps

* Add files to ESlint

* Fix drone typo

* Don't log to console in CI

* Use go test http server

* Add build step before tests

* Move shared init function to common package

* fix drone

* Clean up tests

* Fix linting

* Better mocking for page + version string

* Cleanup test generation

* Remove dependency on gitea binary

* Fix linting

* add initial support for running specific tests

* Add ACCEPT_VISUAL variable

* don't require git-lfs

* Add initial documentation

* Review feedback

* Add logged in session test

* Attempt fixing drone race

* Cleanup and bump version

* Bump deps

* Review feedback

* simplify installation

* Fix ci

* Update install docs

* 2xx/3xx/4xx/5xx -> http.Status...
* http.StatusFound -> http.StatusTemporaryRedirect
* http.StatusMovedPermanently -> http.StatusPermanentRedirect

* gofumpt -w -l .

* gofumpt -w -l -extra .

* Add linter

* manual fix

* change make fmt

* Add a /user/login landing page option

* Add test case for login landing page

* Fix data race in testlogger

* Update git_helper_for_declarative_test.go

* Show email if the authenticated user owns the profile page being
requested for.

Also removed `setting.UI.ShowUserEmail` as it's documentation says it
only controls the email setting on the explore page

* fix current user check... This prevents a panic as a user must be signed in before ctx.User is called

* fix panic in tests

* try to fix tests

* Update year

* Test CI fail

* Revert change

* User 3 is not allowed to authorize

* Set user2 email to be private

* Change to user4 in explore page as user2 now has private email option set

* fix not respecting landing page setting

* fmt

* add landing page test

The e-mail address is currently only hidden from the explore page.