Wiki mirroring implementation (#3233)

* Implement wiki mirroring, add Update mirrors operation to admin dashboard

* bindata.go update after merge

* Implement checking Git repo endpoint existence, support for BB included

* Remove admin dashboard operation
Fix bindata.go

* Apply gofmt to repo model file

* Try to remove bindata from PR

* Revert accepted wiki names change in favor of better system

* Remove unused imports

templates/repo/wiki/start.tmpl

@@ -6,7 +6,7 @@
 			<span class="mega-octicon octicon-book"></span>
 			<h2>{{.i18n.Tr "repo.wiki.welcome"}}</h2>
 			<p>{{.i18n.Tr "repo.wiki.welcome_desc"}}</p>
-			{{if .IsRepositoryWriter}}
+			{{if and .IsRepositoryWriter (not .IsRepositoryMirror)}}
 				<a class="ui green button" href="{{.RepoLink}}/wiki/_new">{{.i18n.Tr "repo.wiki.create_first_page"}}</a>
 			{{end}}
 		</div>