feat(rm): Add Torch Unit Test Suite

Unit test test suite for PyTorch utilizing FxImporter to lower PyTorch graphs to Torch-MLIR then to TOSA IR. Current infrastructure is mostly based on the existing TF/TFL frameworks test suite.

Also includes a small update to TF/TFL framework tests to increase the coverage of scatter_nd tests.

Finally, it updates CI and pre-commit hooks to respect setup.cfg's testpaths value when searching for unit tests.

Note: these commits will not be squashed and instead kept as separate commits in the history