Parameter estimation on cWB-BBH triggers

Currently parameter estimation is disabled on a superevent whose preferred event is from the cWB-BBH pipeline. It can happen when only cWB BBH triggers pass the CBC FAR threshold. Such an event can be CBC signal with significant precession/higher-order moments, and is worth following up with PE. On the other hand, PE requires chirp mass as an input parameter to determine analysis settings.

One simplest way to enable it is to read in chirp mass from a cWB trigger. We need to do tests to check if PE pipelines are compatible with cWB-BBH event format, and fixes are required if they are not.

If the recovery accuracy of chirp mass from the cWB-BBH pipeline is an issue, we could use the most significant triggers among uploads from CBC pipelines. This obviously has a corner case that a superevent only has uploads from cWB-BBH.