- Rename, document the supporting functions for improved clarity
- Drop dim argument from (former) surface_normal

Co-authored-by: Alex Fikl <alexfikl@gmail.com>

Do not use CL-specific max, min, sum

The function registry bits are only relevant for symbolic operators,
and the broadcasting test duplicates what's already being done in
arraycontext.

This ensures that the symbolic stuff remains tested until we remove it.

https://github.com/inducer/modepy/pull/38#issuecomment-846472970

Improved miniforge download URL from @isuruf