feat: method for getting the MFAEnfored resource attribute

closes PRX-313

config-templates/perun_attributes.php

@@ -252,6 +252,11 @@ $config = [
         'ldap' => 'capabilities',
         'type' => 'array',
     ],
+    'perunResourceAttribute_MFAEnforced' => [
+        'rpc' => 'urn:perun:resource:attribute-def:def:proxyMFAEnforced',
+        'ldap' => 'proxyMFAEnforced',
+        'type' => 'bool',
+    ],
 
     /*
      * ENTITYLESS ATTRIBUTES