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>

modules/structs/admin_user.go

@@ -19,6 +19,7 @@ type CreateUserOption struct {
 	Password           string `json:"password" binding:"Required;MaxSize(255)"`
 	MustChangePassword *bool  `json:"must_change_password"`
 	SendNotify         bool   `json:"send_notify"`
+	Visibility         string `json:"visibility" binding:"In(,public,limited,private)"`
 }
 
 // EditUserOption edit user options
@@ -43,4 +44,5 @@ type EditUserOption struct {
 	ProhibitLogin           *bool   `json:"prohibit_login"`
 	AllowCreateOrganization *bool   `json:"allow_create_organization"`
 	Restricted              *bool   `json:"restricted"`
+	Visibility              string  `json:"visibility" binding:"In(,public,limited,private)"`
 }