Severity Enum (#14620)

* Severity Enum
Replace old Alert constants

* Fix whitespace

* Additional uses

* style fixes

* Fix test too

* More missed locations

* More

LibreNMS/Enum/Severity.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace LibreNMS\Enum;
+
+enum Severity: int
+{
+    case Unknown = 0;
+    case Ok = 1;
+    case Info = 2;
+    case Notice = 3;
+    case Warning = 4;
+    case Error = 5;
+}