Custom SMTP Settings (#561)

* Custom SMTP Settings

* Fix lint

* Custom SMTP add in Pricing plan

* Allow reset email settings

* improve custom SMTP using seprate abstract class

* test case for custom SMTP

* fix test case

* UI improvement

* add CASHIER_KEY in phpunit for testcase

* Attempt to fix tests

* Run pint and attempt to fix cache tests

* Fix user management tests

* Fix code linters

* Merged main & fix linting

---------

Co-authored-by: Julien Nahum <julien@nahum.net>

api/config/mail.php

@@ -45,6 +45,17 @@ return [
             'auth_mode' => null,
         ],
 
+        // Use the custom_smtp mailer for the user's own SMTP server.
+        // This configuration will be set dynamically by the AbstractEmailIntegrationHandler class.
+        'custom_smtp' => [
+            'transport' => 'smtp',
+            'host' => null,
+            'port' => 587,
+            'encryption' => 'tls',
+            'username' => null,
+            'password' => null,
+        ],
+
         'ses' => [
             'transport' => 'ses',
         ],