Introduce consistent naming scheme across module

[behackl]

This PR renames a lot of functions in our package to make sure that they follow a more consistent naming scheme.

Deprecation warnings are also introduced for core interface functions that appeared in the arXiv paper on the smooth case (in particular, diagonal_asy and kronecker).

[behackl]

For the sake of convenience, I have used the abbreviation

sage: from sage_acsv import diagonal_asymptotics_diagonal as diagonal
sage: diagonal(1/(1 - x - y))

in case you dislike this, this change can be reverted easily. I have not touched anything in the paper/ directory.

[turnip314]

Mostly minor changes. Main thing is maybe MinimalCriticalCombinatorial should also have a deprecation warning.

[behackl]

Thanks for the review, @turnip314! I'm merging this now, I think this is now more or less safe to base further changes on without the risk of running into significant merge conflicts. :-)