Move Mailman systemd service operations to a separate action

We will now skip any interactions with the Mailman service if
it is not actoive at the start of the conversion.
By default, mailman is not configured and the service will fail to start.
Therefore, attempts to start it during the revert or finishing stage
will also fail.

pleskdistup/actions/systemd.py

@@ -89,7 +89,6 @@ def __init__(self) -> None:
             "drwebd.service",
             "fail2ban.service",
             "httpd.service",
-            "mailman.service",
             "mariadb.service",
             "named-chroot.service",
             "plesk-ext-monitoring-hcd.service",
@@ -176,6 +175,33 @@ def _revert_action(self) -> action.ActionResult:
         return action.ActionResult()
 
 
+# We need to handle the mailman service separately because it is not configured and is stopped by default
+# If we try to start an unconfigured service, it will fail, causing issues during the revert and finish stages
+class HandleMailmanService(action.ActiveAction):
+    mailman_service: str
+
+    def __init__(self) -> None:
+        self.name = "handle mailman service"
+        self.mailman_service = "mailman.service"
+
+    def _is_required(self) -> bool:
+        return systemd.is_service_startable(self.mailman_service) and systemd.is_service_active(self.mailman_service)
+
+    def _prepare_action(self) -> action.ActionResult:
+        util.logged_check_call(["/usr/bin/systemctl", "stop", self.mailman_service])
+        util.logged_check_call(["/usr/bin/systemctl", "disable", self.mailman_service])
+        return action.ActionResult()
+
+    def _post_action(self) -> action.ActionResult:
+        util.logged_check_call(["/usr/bin/systemctl", "enable", self.mailman_service])
+        return action.ActionResult()
+
+    def _revert_action(self) -> action.ActionResult:
+        util.logged_check_call(["/usr/bin/systemctl", "enable", self.mailman_service])
+        util.logged_check_call(["/usr/bin/systemctl", "start", self.mailman_service])
+        return action.ActionResult()
+
+
 class StartPleskBasicServices(action.ActiveAction):
     plesk_basic_services: typing.List[str]