Before:
* `{{.locale.Tr ...}}`
* `{{$.locale.Tr ...}}`
* `{{$.root.locale.Tr ...}}`
* `{{template "sub" .}}`
* `{{template "sub" (dict "locale" $.locale)}}`
* `{{template "sub" (dict "root" $)}}`
* .....
With context function: only need to `{{ctx.Locale.Tr ...}}`
The "ctx" could be considered as a super-global variable for all
templates including sub-templates.
To avoid potential risks (any bug in the template context function
package), this PR only starts using "ctx" in "head.tmpl" and
"footer.tmpl" and it has a "DataRaceCheck". If there is anything wrong,
the code can be fixed or reverted easily.
The admin config page has been broken for many many times, a little
refactoring would make this page panic.
So, add a test for it, and add another test to cover the 500 error page.
Co-authored-by: Giteabot <teabot@gitea.io>
Partially for #24457
Major changes:
1. The old `signedUserNameStringPointerKey` is quite hacky, use
`ctx.Data[SignedUser]` instead
2. Move duplicate code from `Contexter` to `CommonTemplateContextData`
3. Remove incorrect copying&pasting code `ctx.Data["Err_Password"] =
true` in API handlers
4. Use one unique `RenderPanicErrorPage` for panic error page rendering
5. Move `stripSlashesMiddleware` to be the first middleware
6. Install global panic recovery handler, it works for both `install`
and `web`
7. Make `500.tmpl` only depend minimal template functions/variables,
avoid triggering new panics
Screenshot:
<details>
![image](https://user-images.githubusercontent.com/2114189/235444895-cecbabb8-e7dc-4360-a31c-b982d11946a7.png)
</details>