new fencing module for HP servers hosted at online.net

the fence_online module uses the python-hpilo library to access the bmc, and the online web rest-api using python-requests and python-slumber to request a bmc session, username and password.
There is also some infrastructure in it ready to just use the online api, which is currently buggy in displaying the server status, which is why it's recommended to use the ilo method.