Refactor commentTags functionality (#17558)

* feat: Allow multiple tags on comments

- Allow for multiples tags(Currently Poster + {Owner, Writer}).
- Utilize the Poster tag within the commentTag function and remove the
checking from templates.
- Use bitwise on CommentTags to enable specific tags.
- Don't show poster tag(view_content.tmpl) on the initial issue comment.

* Change parameters naming

* Change function name

* refactor variable wording

* Merge 'master' branch into 'tags-comments' branch

* Change naming

* `tag` -> `role`

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

models/issue.go

@@ -71,7 +71,7 @@ type Issue struct {
 	IsLocked bool `xorm:"NOT NULL DEFAULT false"`
 
 	// For view issue page.
-	ShowTag CommentTag `xorm:"-"`
+	ShowRole RoleDescriptor `xorm:"-"`
 }
 
 var (