Add flag for O2Replay channels
Adds flag --o2replay
that can be used on the command line to allow the user to use O2Replay strain channel names,
{'H1': 'H1:GDS-CALIB_STRAIN_O2Replay', 'L1': 'L1:GDS-CALIB_STRAIN_O2Replay', ’V1': 'V1:Hrec_hoft_16384Hz_O2Replay'}
The default channel names are still as described here: https://wiki.ligo.org/LSC/JRPComm/ObsRun3