Add config options to hide issue events (#17414)

* Add config option to hide issue events
Adds a config option `HIDE_ISSUE_EVENTS` to hide most issue events (changed labels, milestones, projects...) on the issue detail page.
If this is true, only the following events (comment types) are shown:
* plain comments
* closed/reopned/merged
* reviews

* Make configurable using a list

* Add docs

* Add missing newline

* Fix merge issues

* Allow changes per user settings

* Fix lint

* Rm old docs

* Apply suggestions from code review

* Use bitsets

* Rm comment

* fmt

* Fix lint

* Use variable/constant to provide key

* fmt

* fix lint

* refactor

* Add a prefix for user setting key

* Add license comment

* Add license comment

* Update services/forms/user_form_hidden_comments.go

Co-authored-by: Gusted <williamzijl7@hotmail.com>

* check len == 0

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: Gusted <williamzijl7@hotmail.com>
Co-authored-by: 6543 <6543@obermui.de>

services/pull/pull.go

@@ -108,7 +108,7 @@ func NewPullRequest(ctx context.Context, repo *repo_model.Repository, pull *mode
 		}
 
 		ops := &models.CreateCommentOptions{
-			Type:        models.CommentTypePullPush,
+			Type:        models.CommentTypePullRequestPush,
 			Doer:        pull.Poster,
 			Repo:        repo,
 			Issue:       pr.Issue,