Custom action similar to drd actions

Problem/Motivation

For custom actions it seems that the PHP code is based to the remote site, meaning your class is not really a class but just a PHP script.

Steps to reproduce

Proposed resolution

Add an option to treat custom actions the same way as drd / drd_agent actions are treated.

Remaining tasks

Add code

User interface changes

None, config will be set in settings.php

API changes

None

Data model changes

None