Make wiki default branch name changable (#29603)

Fix #29000
Fix #28685
Fix #18568

Related: #27497

And by the way fix #24036, add a Cancel button there (one line)

models/migrations/migrations.go

@@ -562,6 +562,8 @@ var migrations = []Migration{
 	NewMigration("Use Slug instead of ID for Badges", v1_22.UseSlugInsteadOfIDForBadges),
 	// v288 -> v289
 	NewMigration("Add user_blocking table", v1_22.AddUserBlockingTable),
+	// v289 -> v290
+	NewMigration("Add default_wiki_branch to repository table", v1_22.AddDefaultWikiBranch),
 }
 
 // GetCurrentDBVersion returns the current db version