Make better use of i18n (#20096)

* Prototyping

* Start work on creating offsets

* Modify tests

* Start prototyping with actual MPH

* Twiddle around

* Twiddle around comments

* Convert templates

* Fix external languages

* Fix latest translation

* Fix some test

* Tidy up code

* Use simple map

* go mod tidy

* Move back to data structure

- Uses less memory by creating for each language a map.

* Apply suggestions from code review

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

* Add some comments

* Fix tests

* Try to fix tests

* Use en-US as defacto fallback

* Use correct slices

* refactor (#4)

* Remove TryTr, add log for missing translation key

* Refactor i18n

- Separate dev and production locale stores.
- Allow for live-reloading in dev mode.

Co-authored-by: zeripath <art27@cantab.net>

* Fix live-reloading & check for errors

* Make linter happy

* live-reload with periodic check (#5)

* Fix tests

Co-authored-by: delvh <dev.lh@web.de>
Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: zeripath <art27@cantab.net>

templates/repo/release/list.tmpl

@@ -65,7 +65,7 @@
 				<li class="ui grid">
 					<div class="ui four wide column meta mt-2">
 						{{if .IsTag}}
-							{{if .CreatedUnix}}<span class="time">{{TimeSinceUnix .CreatedUnix $.i18n.Lang}}</span>{{end}}
+							{{if .CreatedUnix}}<span class="time">{{TimeSinceUnix .CreatedUnix $.i18n}}</span>{{end}}
 						{{else}}
 							{{if .IsDraft}}
 								<span class="ui yellow label">{{$.i18n.Tr "repo.release.draft"}}</span>
@@ -132,7 +132,7 @@
 									{{$.i18n.Tr "repo.released_this"}}
 								</span>
 								{{if .CreatedUnix}}
-									<span class="time">{{TimeSinceUnix .CreatedUnix $.i18n.Lang}}</span>
+									<span class="time">{{TimeSinceUnix .CreatedUnix $.i18n}}</span>
 								{{end}}
 								{{if not .IsDraft}}
 									| <span class="ahead"><a href="{{$.RepoLink}}/compare/{{.TagName | PathEscapeSegments}}...{{.Target | PathEscapeSegments}}">{{$.i18n.Tr "repo.release.ahead.commits" .NumCommitsBehind | Str2html}}</a> {{$.i18n.Tr "repo.release.ahead.target" .Target}}</span>