MoE TensorParallel with Eager

[kshitij12345]

Changes:

• Refactor MoE implementation from test_networks.py into a separate file.
• Adds parallelization plan to the MoE using DTensor and checks that it runs fine with eager.

Time taken by the new test: ~4s

Running 1 items in this shard

thunder/tests/distributed/test_moe.py .                                                                                                                                                      [100%]

================================================================================== 1 passed, 2 warnings in 4.10s ===================================================================================

Almost same as #2478 except for some refactor and the branch lives on lightning-thunder repo instead of a fork to please the CI.

[crcrpar]

looks good to me

[t-vi]

Thank you @kshitij12345 @crcrpar