Add Visible modes function from Organisation to Users too (#16069)

You can limit or hide organisations. This pull make it also posible for users

- new strings to translte
- add checkbox to user profile form
- add checkbox to admin user.edit form
- filter explore page user search
- filter api admin and public user searches
- allow admins view "hidden" users
- add app option DEFAULT_USER_VISIBILITY
- rewrite many files to use Visibility field
- check for teams intersection
- fix context output
- right fake 404 if not visible

Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: Andrew Thornton <art27@cantab.net>

services/forms/user_form.go

@@ -12,6 +12,7 @@ import (
 
 	"code.gitea.io/gitea/modules/context"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/structs"
 	"code.gitea.io/gitea/modules/web/middleware"
 
 	"gitea.com/go-chi/binding"
@@ -230,6 +231,7 @@ type UpdateProfileForm struct {
 	Location            string `binding:"MaxSize(50)"`
 	Language            string
 	Description         string `binding:"MaxSize(255)"`
+	Visibility          structs.VisibleType
 	KeepActivityPrivate bool
 }