Protected branches system (#339)

* Protected branches system

* Moved default branch to branches section (`:org/:reponame/settings/branches`).
* Initial support Protected Branch.
  - Admin does not restrict
  - Owner not to limit
  - To write permission restrictions

* reformat tmpl

* finished the UI and add/delete protected branch response

* remove unused comment

* indent all the template files and remove ru translations since we use crowdin

* fix the push bug

models/migrations/migrations.go

@@ -82,6 +82,8 @@ var migrations = []Migration{
 	NewMigration("create user column allow create organization", createAllowCreateOrganizationColumn),
 	// V16 -> v17
 	NewMigration("create repo unit table and add units for all repos", addUnitsToTables),
+	// v17 -> v18
+	NewMigration("set protect branches updated with created", setProtectedBranchUpdatedWithCreated),
 }
 
 // Migrate database to current version