Restructure where models are stored (#1476)

The idea is to clean the repository a little bit by moving models into their respective folders.

app/Http/Controllers/Contacts/IntroductionsController.php

@@ -2,8 +2,8 @@
 
 namespace App\Http\Controllers\Contacts;
 
-use App\Gift;
-use App\Contact;
+use App\Models\Contact\Gift;
+use App\Models\Contact\Contact;
 use App\Http\Controllers\Controller;
 use App\Http\Requests\People\IntroductionsRequest;
 use Illuminate\Database\Eloquent\ModelNotFoundException;