Packaging

[leosaffin]

Various updates for packaging

1. Use pyproject.toml
2. Add automated tests
3. Add documentation with sphinx (we will need to add the extras for readthedocs still)
4. Ruff format/check fixes (lower case)
5. Update version number to 1.0.0

A few changes to the module itself

1. Lower case function names
2. Rearrange where/what is importable
3. Vectorise VT computation
4. Remove need for sorting by pressure levels
5. Have pressure levels as an optional input to main function (and VT)
6. Simplify area weighting
7. Use huracanpy for angle calculation

I've also added a script for a speed test. All of these changes have been neutral or an improvement. Biggest improvement was vectorising the VT calculation (built in to the scipy function) rather than using a list comprehension. If there was a good reason for doing that, feel free to revert.

[leosaffin]

Turns out vectorized linregress is a fairly new thing. Needed to update python/scipy versions to match, but it is in line with which python versions xarray supports, so I think it's OK

[leosaffin]

Might be worth running the copilot thing in #4 again on this. I think I've fixed most, but not all, of the issues it raised

[stella-bourdin]

Might be worth running the copilot thing in #4 again on this. I think I've fixed most, but not all, of the issues it raised

Copilot doesn't want to work on cross-repo PRs, but I'll merge this one and then ask it to update the audit in #4