Fix formatting bash/venv environments

[brryan]

Background

./style/format.sh is failing on some platforms due to not finding either clang-format or black. This PR itself really just adds a darwin frontend environment to simplify formatting, basically, when working on darwin without needing to get a backend allocation, but complementary to this I've updated the environments on darwin, chicoma, and venado.

Description of Changes

• add darwin-fe partition
• add black to skylake-gold
• add black to volta-x86
• add virtual python environment to chicoma-cpu (also used by chicoma frontend)
• install clang-format/12 to chicoma-cpu environment
• install clang-format/12 and black to chicoma-gpu` environment
• rfe venado-cpu
• rfe venado-gpu
• fe venado-cpu
• fe venado-gpu
• Updated groups/permissions for all python environments

Checklist

• New features are documented
• Tests added for bug fixes and new features
• (@lanl.gov employees) Update copyright on changed files