Add option to use array for autoloading permissions

[groovenectar]

Example usage in users.php in the Users plugin:

'Auth' => [
	'RbacPolicy' => [
		'adapter' => [
			'autoload_config' => [
				'MyPlugin.permissions',
				'MyOtherPlugin.permissions',
				'permissions',
			],
		],
	],
],

Since the array is optional, it should not break existing implementations

[groovenectar]

I'll update per the test results on this file

[rochamarcelo]

Would be nice to have some info in documentation pages.