Split migrations folder (#21549)

There are too many files in `models/migrations` folder so that I split
them into sub folders.

models/migrations/v1_11/v110.go

@@ -0,0 +1,30 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package v1_11 //nolint
+
+import (
+	"xorm.io/xorm"
+	"xorm.io/xorm/schemas"
+)
+
+func ChangeReviewContentToText(x *xorm.Engine) error {
+	switch x.Dialect().URI().DBType {
+	case schemas.MYSQL:
+		_, err := x.Exec("ALTER TABLE review MODIFY COLUMN content TEXT")
+		return err
+	case schemas.ORACLE:
+		_, err := x.Exec("ALTER TABLE review MODIFY content TEXT")
+		return err
+	case schemas.MSSQL:
+		_, err := x.Exec("ALTER TABLE review ALTER COLUMN content TEXT")
+		return err
+	case schemas.POSTGRES:
+		_, err := x.Exec("ALTER TABLE review ALTER COLUMN content TYPE TEXT")
+		return err
+	default:
+		// SQLite doesn't support ALTER COLUMN, and it seem to already make String to _TEXT_ default so no migration needed
+		return nil
+	}
+}