use built-in cache package to wrap external go-chi cache package

Since `modules/context` has to depend on `models` and many other
packages, it should be moved from `modules/context` to
`services/context` according to design principles. There is no logic
code change on this PR, only move packages.

- Move `code.gitea.io/gitea/modules/context` to
`code.gitea.io/gitea/services/context`
- Move `code.gitea.io/gitea/modules/contexttest` to
`code.gitea.io/gitea/services/contexttest` because of depending on
context
- Move `code.gitea.io/gitea/modules/upload` to
`code.gitea.io/gitea/services/context/upload` because of depending on
context

Nowadays, cache will be used on almost everywhere of Gitea and it cannot
be disabled, otherwise some features will become unaviable.

Then I think we can just remove the option for cache enable. That means
cache cannot be disabled.
But of course, we can still use cache configuration to set how should
Gitea use the cache.

Part of #27065

This PR touches functions used in templates. As templates are not static
typed, errors are harder to find, but I hope I catch it all. I think
some tests from other persons do not hurt.

Part of #27065

This reduces the usage of `db.DefaultContext`. I think I've got enough
files for the first PR. When this is merged, I will continue working on
this.

Considering how many files this PR affect, I hope it won't take to long
to merge, so I don't end up in the merge conflict hell.

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

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>

This PR adds a context parameter to a bunch of methods. Some helper
`xxxCtx()` methods got replaced with the normal name now.

Co-authored-by: delvh <dev.lh@web.de>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

* Move access and repo permission to models/perm/access

* fix test

* fix git test

* Move functions sequence

* Some improvements per @KN4CK3R and @delvh

* Move issues related code to models/issues

* Move some issues related sub package

* Merge

* Fix test

* Fix test

* Fix test

* Fix test

* Rename some files

Extract from #19703

Signed-off-by: Andrew Thornton <art27@cantab.net>

Add statistic information for total user count, active user count, issue count and comment count for `/nodeinfo`

Nodeinfo is a way to expose certain metadata about a server for use of discovery regarding functionality of its federation capabilities.

Two endpoints are required:
1. `/.well-known/nodeinfo` which informs client where it can find the location of the location of its metadata (including which version of the schema is used)
2. the endpoint which exposes the metadata in json format according to schema.

Notes:
* `openRegistrations` is a required field, but I propose to set to false as default in case someone writes a crawler to discover "open" gitea instances
* to limit data leakage I also propose to not include the `usage` field (note it is required so it should be included, but left as empty).

More info:
https://github.com/jhass/nodeinfo
https://github.com/jhass/nodeinfo/tree/main/schemas/2.1
http://nodeinfo.diaspora.software/protocol.html