FEATURE: move user roles into separate enumeration.

This commit moves list of user roles into separate class (with own namespace), so we can access this data anywhere from application.

app/Enumerations/UserRoles.php

@@ -0,0 +1,35 @@
+<?php
+namespace App\Enumerations;
+
+use App\Models\User;
+
+class UserRoles
+{
+    /**
+     * Getter for roles
+     *
+     * This method returns only list of roles as inserted into database
+     *
+     * @return array
+     */
+    public static function getSimple()
+    {
+        return array_values(self::getWithTranslations());
+    }
+
+    /**
+     * Getter for roles with translations
+     *
+     * This method returns all user roles as keys. Values are strings used for translations.
+     *
+     * @return array
+     */
+    public static function getWithTranslations()
+    {
+        return [
+            User::ROLE_ADMIN   => 'admin/userManagement.role_' . User::ROLE_ADMIN,
+            User::ROLE_EDITOR  => 'admin/userManagement.role_' . User::ROLE_EDITOR,
+            User::ROLE_VISITOR => 'admin/userManagement.role_' . User::ROLE_VISITOR
+        ];
+    }
+}