1. use MockVariableValue as much as possible
2. use wg.Go as much as possible instead of Add/Done
3. simplify global lock's DefaultLocker logic to make it easier to test
4. introduce a general approach for getting external service config in
CI
5. remove unclear & unnecessary "t.Skip"
6. use modern generic syntax for remaining "DecodeJSON" calls
7. clarify test result for "list gitignore templates" and "list
licenses"
This adds a API for getting License templates. This tries to be as close
to the [GitHub
API](https://docs.github.com/en/rest/licenses?apiVersion=2022-11-28) as
possible, but Gitea does not support all features that GitHub has. I
think they should been added, but this out f the scope of this PR. You
should merge #23006 before this PR for security reasons.
