Replace #22117. Implement it in a more maintainable way.

Some licenses have placeholders e.g. the BSD licenses start with this
line:
```
Copyright (c) <year> <owner>. 
```
This PR replaces the placeholders with the correct value when initialize
a new repo.

### FAQ

- Why not use a regex?
It will be a pretty complicated regex which could be hard to maintain.

- There're still missing placeholders.
There are over 500 licenses, it's impossible for anyone to inspect all
of them alone. Please help to add them if you find any, and it is also
OK to leave them for the future.

---------

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

This will ensure that the file always has a final newline. I'm not sure
where this bug with inconsistent final newline actually comes from, it
is likely Windows-related.

---------

Co-authored-by: delvh <dev.lh@web.de>

None of the features of `unrolled/render` package is used. 

The Golang builtin "html/template" just works well. Then we can improve
our HTML render to resolve the "$.root.locale.Tr" problem as much as
possible.

Next step: we can have a template render pool (by Clone), then we can
inject global functions with dynamic context to every `Execute` calls.
Then we can use `{{Locale.Tr ....}}` directly in all templates , no need
to pass the `$.root.locale` again and again.

This PR just consumes the
[hcaptcha](https://gitea.com/jolheiser/hcaptcha) and
[haveibeenpwned](https://gitea.com/jolheiser/pwn) modules directly into
Gitea.

Also let this serve as a notice that I'm fine with transferring my
license (which was already MIT) from my own name to "The Gitea Authors".

Signed-off-by: jolheiser <john.olheiser@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>

close #21176

We can not have the `frontend` target depend on golang because of they
way drone is set up. Move the `go-licenses` generation back into `tidy`
where it will now also be checked for consistency during `tidy-check`.

(I assume all `main` branch builds should currently fail [like
this](https://drone.gitea.io/go-gitea/gitea/60244/1/11)).

The reasony why it shouldn't be treated the same as for example `go
generate` is because output files are checked in. tidy is imho the
optimal target to run this after.

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

This removes the JS dependency in the checks pipeline. JSON output is
different because the previous JS did indent the license data
differently and a JSON key was changed, but the end result is the same
as it gets re-indented by wepack.

Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: zeripath <art27@cantab.net>