(WIP) allow for a customized region on the receipt page that is microsite bran...

...d specific
Note to reviewers, this is needed because of an oversight in the original microsite make template overrides. If a parent template is in a subdirectory of lms/templates (e.g. lms/templates/shoppingcart) and has an <! include ... > for a contained child template, then Mako inserts additional relative pathing which ends up being incorrect.

This address it to make it absolute so that Mako does not prepend the parent directory name