Include More detectors

The existing detector list is ['H1', 'L1', 'V1']. There is no way to add any new detectors (which are not still present in the existing detector list ) in ini file of bilby_pipe without editing the source code locally.

The addition of 'K1' as well as 'CE' and 'ET' in the detector list is needed. It will be worth if there is an option to add detectors like bilby.