Housekeeping/clean code up

[CosmoMatt]

Scope crept quite a lot on this but still effectively housekeeping. Main contributions:

Housekeeping

• [x] Restructure code to be more consistant.
• [x] Update api docs inline with above.
• [x] Clean floating files (notebooks from previous work)
• [x] Combine tests into one overloaded pytest function.
• [x] Switch s2fft dependency to v1.0.2

Added features

• [x] Add switch to avoid duplicating highest wavelet scale memory.
• [x] Pull through support for Torch frontend and test
• [x] Add Torch support to all docs and api autodocs
• [x] Pull through support for Gauss-Legendre (GL) sample locations
• [x] Add torch notebook and update across the board

C backend support for SSHT operations

• [x] port through JAX frontend support for C backend.

CI related

• [ ] Enhance codecov to > 90%

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 91.53005% with 31 lines in your changes are missing coverage. Please review.

Project coverage is 91.99%. Comparing base (c5702aa) to head (6394602).

Files	Patch %	Lines
s2wav/filters.py	88.10%	22 Missing :warning:
s2wav/transforms/wavelet_precompute_torch.py	92.30%	4 Missing :warning:
s2wav/samples.py	91.66%	2 Missing :warning:
s2wav/transforms/wavelet.py	93.93%	2 Missing :warning:
s2wav/transforms/construct.py	96.77%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #78 +/- ## ========================================== + Coverage 88.31% 91.99% +3.67% ========================================== Files 8 7 -1 Lines 522 587 +65 ========================================== + Hits 461 540 +79 + Misses 61 47 -14 ```

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[CosmoMatt]

@jasonmcewen I'm not sure I follow. What notebook links do you mean?

[jasonmcewen]

@CosmoMatt There appear to be nblink files in the repo? Remember we chances how the notebooks were set up for colab support in s2fft?