Include Python implementation of COBYLA and associated CI test

[nbelakovski]

Please note that there is some duplicated code between the python/ and pyprima/ folders, notably in __init__.py and files like _nonlinear_constraints.py. Rather than try to link the code between the two I thought it was best to keep them separate, both for packaging purposes and because they are calling into different implementations so I wouldn't want code that's meant to deal with issues that arise due to bindings finding its way into a pure Python implementation, even if it wouldn't do any harm.

[github-advanced-security]

check-spelling found more than 20 potential problems in the proposed changes. Check the Files changed tab for more details.

[nbelakovski]

Something I think you should take a look at: the test for pyprima measures code coverage. If you download one of the artifacts from the test: https://github.com/libprima/prima/actions/runs/14142603647?pr=221 (all 3 should be the same), and open up index.html you can get an idea of which lines of code the tests hit and which they don't. Of course, just because a test runs a particular line of code doesn't really mean anything - it's possible to call a function in a test and throw away the output, and the function will still be marked as "covered". It's not perfect, but it can be useful, particularly for the higher level tooling that translates what a user has provided in the Python interface into something that the function can accept.