Backport #27227 by @denyskon
Throughout the Gitea codebase, you can meet some weird constructions to
make `locale.Tr` work in subtemplates.
Since we now have `ctx.Locale.Tr` which solves that problem, clean up
various templates which pass `locale` through `dict` or use some weird
constructions like `$.root.locale`
Going on, it would be great to replace every case of `$.locale.Tr` and
`.locale.Tr` with `ctx.Locale.Tr`, but that needs to be done with
patience.
Co-authored-by: Denys Konovalov <kontakt@denyskon.de>