[BAZEL] Update the Bazel overlay to use MODULE

[shantanu-gontia]

WORKSPACE are deprecated and to be replaced by MODULE. Bazel roadmap mentions WORKSPACE are going to be removed entirely. Mainline LLVM has also upgraded from WORKSPACE to MODULE.

This PR updates the Torch-MLIR overlay to use MODULE and fixes the bazel build.

1. WORKSPACE -> MODULE
2. Add a .bazelversion to 8.4.0 (parity with mainline LLVM)
3. Update the docker imagefile for the bazel build to use bazelisk
4. Add the AArch64 target to the LLVM Build (to support local builds on Arm)
5. Update test tooling to support the new MODULE system's idiosynracies

[shantanu-gontia]

Hi, @sjain-stanford the wiki listed you as the maintainer for the bazel build. Could you review this PR? Thanks.

[shantanu-gontia]

for FileCheck substitution using @LLVM_TOOLS_DIR@

[sjain-stanford]

Hi, @sjain-stanford the wiki listed you as the maintainer for the bazel build. Could you review this PR? Thanks.

Thanks for the ping. I am no longer overseeing the bazel build for torch-mlir but let me loop in someone who can help.
cc: @mfeliz-cruise , @matthewfl (also, we should update the current set of maintainers if possible)