Hosting - the Aegir frontend
The Aegir frontend is a Drupal site in itself. You can use any Drupal module to extend it.
Adding a module
Add a new module either to the site specific moduled directory e.g.
/var/aegir/hostmaster-7.x-3.x/sites/aegir.example.com/modules or use your own makefile to create the hostmaster platform.
To change one of the content types of views used in the Aegir frontend make sure you have the views_ui and field_ui core modules enabled. You can enable the like any other Drupal module as they are included with code already.