Add a way to mark Conversation (code comment) resolved (#11037)

* Add a way to mark Conversation (code comment) resolved

mark Conversation is a way to mark a Conversation is stale
or be solved. when it's marked as stale, will be hided like
stale. all Pull Request writer , Offical Reviewers and poster
can add or remove Conversation resolved mark.

Signed-off-by: a1012112796 <1012112796@qq.com>

* fix lint

* Apply suggestions from code review

* Add ResolveDoer
* fix ui

Co-Authored-By: Lauris BH <lauris@nix.lv>
Co-Authored-By: 6543 <6543@obermui.de>

* change IsResolved to an function
Add permission check in UpdateResolveConversation

* Apply suggestions from code review

* change return error for permisson check
* add default message for deleted user
* get issue message from comment
* add migration for ``ResolveDoerID`` column

another  change:
* block mark pending review as resolved because it's not necessary

Co-authored-by: guillep2k <18600385+guillep2k@users.noreply.github.com>

* change button color

* resolve button size

* fix code style

* remove unusefull code

Co-authored-by: guillep2k <18600385+guillep2k@users.noreply.github.com>

Co-authored-by: Lauris BH <lauris@nix.lv>
Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: guillep2k <18600385+guillep2k@users.noreply.github.com>

routers/routes/routes.go

@@ -739,6 +739,7 @@ func RegisterRoutes(m *macaron.Macaron) {
 			m.Post("/assignee", reqRepoIssuesOrPullsWriter, repo.UpdateIssueAssignee)
 			m.Post("/request_review", reqRepoIssuesOrPullsReader, repo.UpdatePullReviewRequest)
 			m.Post("/status", reqRepoIssuesOrPullsWriter, repo.UpdateIssueStatus)
+			m.Post("/resolve_conversation", reqRepoIssuesOrPullsReader, repo.UpdateResolveConversation)
 		}, context.RepoMustNotBeArchived())
 		m.Group("/comments/:id", func() {
 			m.Post("", repo.UpdateCommentContent)