Feature/user me controller

[mubbi]

This pull request introduces a new MeController to handle the /me endpoint, replacing the previous inline route logic. It also updates the UserResource to improve handling of token-related attributes, adds a new success message to the localization file, and includes a feature test for the new controller. Below are the most important changes grouped by theme:

New Controller for /me Endpoint:

• Added MeController in app/Http/Controllers/Api/V1/User/MeController.php to handle authenticated user profile requests. This includes loading user roles and permissions and returning a structured JSON response.
• Updated the /me route in routes/api_v1.php to use the new MeController instead of inline logic.

Enhancements to UserResource:

• Modified UserResource in app/Http/Resources/V1/Auth/UserResource.php to check for token-related attributes using array_key_exists and provide default values for optional attributes.

Localization Update:

• Added a new success message 'success' => 'Response returned successfully.' to lang/en/common.php.

Feature Test for /me Endpoint:

• Added a new feature test in tests/Feature/API/V1/User/MeControllerTest.php to verify that the /me endpoint returns the authenticated user's profile with roles and permissions.