Restore command (#593)

Add waiting for changes to config file

Add max size for config files

Restore files

Restore database file

Expose migrate to

Move init stuff to seperate package

Add restoring config file

Co-authored-by: kolaente <k@knt.li>
Reviewed-on: https://kolaente.dev/vikunja/api/pulls/593

pkg/migration/migration.go

@@ -104,6 +104,15 @@ func Rollback(migrationID string) {
 	log.Info("Rolled back successfully.")
 }
 
+// MigrateTo executes all migrations up to a certain point
+func MigrateTo(migrationID string, x *xorm.Engine) error {
+	m := initMigration(x)
+	if err := m.MigrateTo(migrationID); err != nil {
+		return err
+	}
+	return nil
+}
+
 // Deletes a column from a table. All arguments are strings, to let them be standalone and not depending on any struct.
 func dropTableColum(x *xorm.Engine, tableName, col string) error {