Migrate to asteroid-filterbanks

Now that asteroid-filterbanks has been released, we should migrate to it 🎉

Few points:

• Backward compat: this is straightforward, I guess a simple import asteroid_filterbanks as filterbanks with asteroid/__init__.py will do perfectly.
• Source code: Two options (not sure myself)
  • Consider that asteroid.filterbanks is still a thing and keep using it.
  • Replace everything from asteroid.fitlerbanks to asteroid-filterbanks to give the “good example”.
• CI: specific unit tests for filterbanks will be done there but we’ll keep some non-specific tests here. This is cool because it’ll probably drive us to do more thorough testing of the filterbanks themselves, and that’s a good point.
• Docs: that the trickiest IMO. The docs will still be hosted on asteroid’s docs so we have to find a way to make it nicely. Didn’t find this out yet, any help deeply appreciated.

[mpariente]

For the docs, it’s easier than I thought.

In the current filterbank.rst file, I can change asteroid.filterbanks by asteroid_filterbanks and this will retrieve the class and autodoc it. This is really cool !

One downside of this is that the rst file is in asteroid, not in asteroid-filterbanks. This means making a two step process for adding a feature to asteroid-filterbank and adding the docs in asteroid. Ideally, we could do better. However, it’s not meant to change that often and it’s probably fine.

Two other options I imagined that would have the docs folders in asteroid-filterbanls (so that it doesn’t have the flaws of the previous method) but didn’t explore yet:

• Having asteroid-filterbanks as a submodule
• Cloning asteroid-filterbanks during the docs build process

I personally think that the first one is fine, given the state of things.

[mpariente]

Closed by #346