Add support for HoM

[mj-will]

Add support for HoM.

This MR supersedes https://github.com/gwastro/BBHX-waveform-model/pull/2, since Connor is writing up and I'm going to try and get this change in for the various projects that need it.

Summary of changes

• Original changes from Connor's PR
• Add m_mode keyword argument to chirptime and interpolate_tf
• Allow user to set the number of interpolation points num_interp

To-Do

• [x] Plots described in https://github.com/ConWea/BBHX-waveform-model/pull/2

[mj-will]

@WuShichao here are the plots you asked for in https://github.com/ConWea/BBHX-waveform-model/pull/2#discussion_r1568779003:

The solid line corresponds to num_interp=10 (the previous hardcoded value) and the dashed line to num_interp=100 (the proposed default)

Supermassive BBH

Stellar mass BBH

[mj-will]

@spxiwh I've looked at how BBHx is implemented and I don't think it automatically works out a starting frequency anywhere in the code, instead it always uses mf_min (see https://github.com/mikekatz04/BBHx/blob/master/bbhx/waveforms/phenomhm.py#L107).

So I think we can just follow the Phenom convention and set the minium frequency based on highest m mode. For reference, do you know where this is defined in LAL?

[spxiwh]

PyCBC does this here:

https://github.com/gwastro/pycbc/blob/master/pycbc/waveform/waveform.py#L1056

to the best of my knowledge LAL does not do this [properly], if generating f-domain waveforms in the time domain.

[mj-will]

The rebase was going to be a nightmare after the TDI change, so I just merged the changes from main instead.

[WuShichao]

Looks good and reasonable, if you can show the Q-transform of TDI waveform in the call that would be better.