Remove module "weblounge-bridge"

[myniva]

The original purpose of the Weblounge bridge module was to connect third party systems to serve as content producers.

The mail bridge never made it to production quality and only served as proof of concept. Even though the feature itself sounds interesting, the existing code is of no real value and should be removed.

The OAI-PMH harvester (copied from the Opencast project, see http://opencast.org) was used to as base class in a closed-source project. As this is the only known implementation and it not directly relates to Weblounge, it should be safe to remove that part of the module as well.