Add Functionality to create optimal SNR grid from user inputs

Instead of using the example SNR grids provided, the user can now create their own according to whatever noise curve they prefer. User can either input a lalsimnoise function (options listed here: https://git.ligo.org/lscsoft/lalsuite/-/blob/release-20220303/lalsimulation/lib/LALSimNoise.h) or a PSD file. Some example PSD files that might be generally useful have also been uploaded. At the moment, this is done by running python create_snr_grid.py from within sensitivity but eventually I'd like it to have its own config file, or an option in the config file.

#3 (closed)