Make Mesh into a dataclass

[alexfikl]

This starts making Mesh into a dataclass. Right now it's mostly just porting away from pytools.Record, since it's hard to make it a clean dataclass while being backwards compatible.

The main additions are:

• a make_mesh factory function that does all the work of the Mesh constructor.
• a check_mesh_consistency function that does all the checking. This seemed useful to make public, since the dataclass version won't do any checking on replace(mesh, ...) and it may still be wanted sometimes?
• ~get_nodal_adjacency and get_facial_adjacency_groups to replace the property versions.~

~The nodal / facial adjacency attributes were very annoying. Currently it overwrites __getattribute__ to make it behave a bit like before. Let me know if you have some better ideas on how to make that work..~

This is still a WIP, but I had it lying around for a while, so might as well. Things still to do:

• [x] Run the CI and make everything actually works. Currently it works on my machine™
• [x] Left a few remarks / questions below that should be looked at.
• [x] Port at least the internal uses of the various functions to avoid deprecation warnings.
• [x] Not quite sure why the documentation build is failing? It seems to dislike the tikz stuff, but that shouldn't have changed..

[alexfikl]

@inducer I think all of my initial questions are solved now, so this is ready for a proper review.

Port at least the internal uses of the various functions to avoid deprecation warnings.

I'm thinking of leaving this for a followup PR, since this is sufficiently big?

[inducer]

Pushed a commit that ports the internal uses of Mesh(). Mostly a sed job.

[inducer]

I guess I sort of understand why you might have changed the make_mesh arguments to groups, *, vertices, but I don't think it's worth the headache. 99% of meshes have vertices, and the 1% that don't can just pass None for that first argument.

[alexfikl]

I guess I sort of understand why you might have changed the make_mesh arguments to groups, *, vertices, but I don't think it's worth the headache. 99% of meshes have vertices, and the 1% that don't can just pass None for that first argument.

That's fair enough. It definitely makes the porting easier :grin: Thanks for helping with that and fixing all the issues!

[inducer]

Thanks for getting this most of the way!