PATH update for host models

[cwjames1983]

This is a pretty big one, apologies - all the following works were being co-developed, and could not be nicely separated. It incorporates the following works:

Model of FRB hosts, as described in optical.py, optical_numerics.py, and optical_params.py in the core zdm codebase. This is the core of the work for the updated PATH paper, the calculations for which are given in papers/pathpriors. It also includes data from Nick Loudas - I decided to include his data in the repository, even though it's O~1 MB - in zdm/data/optical/

Calculations for Rubin paper, and initial model of p(m) from Marnoch et al. This is under papers/lsst. The name of the branch inherits from Bryce Smith, who did some Monte Carlo work for this paper. - and named the relevant branch "test".

Calculations for an SKA science chapter, under papers/SKA_science. I was unsure whether or not to keep this in the repository, but felt that having some record of what the SKA thinks it can do could be useful.

CRACO modelling - this contributes to both Jordan's current work, of combining FRB observations from ASKAP into a single effective survey, and also a paper in prep by Andy and I analysing the FRB rate produced by CRACO in various modes.

CASATTA - estimates of CASATTA sensitivity under pspers/casatta for ATNF 2030 Futures meeting. I expect this will continue to be developed as the CASATTA concept becomes more refined

[profxj]

I ignored most of the files in papers/ and focused on the optical modules.

I'm also about to issue a PR to this branch of Claude generated docs

[profxj]

go for it!