Added usage check to delete endpoints

lang/en/exceptions.php

@@ -2,6 +2,7 @@
 
 declare(strict_types=1);
 
+use App\Exceptions\Api\EntityStillInUseApiException;
 use App\Exceptions\Api\InactiveUserCanNotBeUsedApiException;
 use App\Exceptions\Api\TimeEntryCanNotBeRestartedApiException;
 use App\Exceptions\Api\TimeEntryStillRunningApiException;
@@ -15,5 +16,6 @@ return [
         TimeEntryCanNotBeRestartedApiException::KEY => 'Time entry is already stopped and can not be restarted',
         InactiveUserCanNotBeUsedApiException::KEY => 'Inactive user can not be used',
         UserIsAlreadyMemberOfProjectApiException::KEY => 'User is already a member of the project',
+        EntityStillInUseApiException::KEY => 'The :modelToDelete is still used by a :modelInUse and can not be deleted.',
     ],
 ];

lang/en/validation.php

@@ -202,4 +202,16 @@ return [
     'currency' => 'The :attribute field must be a valid currency code (ISO 4217).',
     'organization' => 'The :attribute does not exist.',
     'task_belongs_to_project' => 'The :attribute is not part of the given project.',
+
+    'entities' => [
+        'organization' => 'organization',
+        'project' => 'project',
+        'task' => 'task',
+        'time_entry' => 'time entry',
+        'user' => 'user',
+        'client' => 'client',
+        'member' => 'member',
+        'project_member' => 'project member',
+        'tag' => 'tag',
+    ],
 ];