Fluids naming consistency

[jrwrigh]

(More to be added as I find them, just making one central location for them so I don't forget).

• Use qfctx for CeedQFunctionContext objects, and ctx for the structs themselves
  • The inconsistent format is to use context for CeedQFunctionContext and ctx for the structs

[jrwrigh]

Another misc task: Move the comments describing functions in navierstokes.h into docstrings in the function. Doesn't make much sense to have them in the header file, especially when their redundant to the name of the function (yay for good function names though!).

[jeremylt]

This would probably be transferred to the HONEE repo?

[jrwrigh]

Yeah, that works.

[jrwrigh]

https://gitlab.com/phypid/honee/-/issues/9