Feature migrations up/down (#270)

* Migrations up down

* Add forum model

* Syntactic sugar for db structure changes

* Refactor migrations with $up & $down

* Fix migrations upgrade and downgrade

+ Add option to disable auto migrate

* Add migrate:to command

Usage: php aac migrate:to x (x - database version)

* Show error when mail is not enabled

* Fixes regarding to init.php

* Add migrate command to manually upgrade db, incase auto migrate is disabled

* Fixed rest of the migrations

* Limit max version of database

* Don't allow minus number

* Option to clear specified plugin settings by name

* Version is required

* Fix PHPStan errors

* Unset $up after migration, to prevent executing same migration twice

* Add database version to output

* This is not needed

* Update 5.php

* Set database_auto_migrate on install

* Set blank & color only if current db version supports it

* Fix duplicate function declaration

system/settings.php

@@ -392,6 +392,13 @@ return [
 			'default' => false,
 			'is_config' => true,
 		],
+		'database_auto_migrate' => [
+			'name' => 'Database Auto Migrate',
+			'desc' => 'Migrate database to latest version in myaac, automatically.',
+			'type' => 'boolean',
+			'default' => true,
+			'is_config' => true,
+		],
 		[
 			'type' => 'category',
 			'title' => 'Mailing',