Remove use of local rank in trainers

[rayg1234]

Remove use local_rank to set cuda devices all together. Previously this was behind a feature flag but instead of maintaining the 2 versions, its easier to just consolidate since the local multiple-GPU runs are bugged right now and multiple ranks can be assigned on the same device. Each rank now will only see their local GPU (GPU-0) and not 8 devices.

After this there shouldn't be any code that tries to assign a cuda device that isn't "cuda" or "cuda:0".

To sanity check:

• Local 1 rank run
• Local N rank run
• Cluster run

[codecov]

Codecov Report

Attention: Patch coverage is 33.33333% with 2 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/fairchem/core/common/distutils.py	50.00%	1 Missing ⚠️
src/fairchem/core/trainers/base_trainer.py	0.00%	1 Missing ⚠️

Files with missing lines	Coverage Δ
src/fairchem/core/_cli_hydra.py	69.73% <ø> (-0.42%)	⬇️
src/fairchem/core/trainers/ocp_trainer.py	69.66% <ø> (ø)
src/fairchem/core/common/distutils.py	57.04% <50.00%> (+0.49%)	⬆️
src/fairchem/core/trainers/base_trainer.py	87.19% <0.00%> (+0.19%)	⬆️

[misko]

LGTM! Looks great!