add script for offline pastros

Single script for computing offline pastros from scratch.

Presentation: (slides, minutes)

• Single command line script that does it all (Takes top level inputs/paths from a config file)
• All population modelling for injections and VTs done using gw-distributions. (Models can be easily changed by changing the gw-distribution config files that are taken as input)
• Nothing (including source categories) is hard coded.
• Cumulative output file will replace “O1O2O3 fgmc” for O4b. No code change will be required.

$ singularity exec /path/to/image/gstlal-dev/ offline_pastro /path/to/config.yaml

Example config: in pastro/examples/fgmc/offline/

Preliminary results from O1+O2+MDC11