Split the importer module out from the installer module (#468)

* Split the importer module out from the installer module

* Cleanup of unused imports

* Move updater into separate module #453

* Remove unused imports/formatting

* Disable the install and importer modules at the end of the setup

* Unused imports; update IJ style

* test explicit stage for php+mysql

* add more to matrix

* Add different MariaDB versions

* undo

modules/Installer/Config/config.php

@@ -37,8 +37,4 @@ return [
         'storage/framework/views',
         'storage/logs',
     ],
-
-    'importer' => [
-        'batch_size' => 20,
-    ],
 ];