Add commit statuses reports on pull request view (#6845)

* Add commit statuses reports on pull view

* Add some translations

* improve the UI

* fix fmt

* fix tests

* add a new test git repo to fix tests

* fix bug when headRepo or headBranch missing

* fix tests

* fix tests

* fix consistency

* fix tests

* fix tests

* change the test repo

* fix tests

* fix tests

* fix migration

* keep db size consistency

* fix translation

* change commit hash status table unique index

* remove unused table

* use char instead varchar

* make hashCommitStatusContext private

* split merge section with status check on pull view ui

* fix tests; fix arc-green theme on pull ui

templates/repo/issue/view_content/pull.tmpl

@@ -45,7 +45,8 @@
 	{{else if .Issue.PullRequest.CanAutoMerge}}green
 	{{else}}red{{end}}"><span class="mega-octicon octicon-git-merge"></span></a>
 	<div class="content">
-		<div class="ui merge segment">
+		{{template "repo/pulls/status" .}}
+		<div class="ui attached merge-section segment">
 			{{if .Issue.PullRequest.HasMerged}}
 				<div class="item text purple">
 					{{$.i18n.Tr "repo.pulls.has_merged"}}