cleanup: share components of verilog emitter and tfhe-rs emitter

[asraa]

Likely flattening indices with values, for e.g.

[github-actions[bot]]

This issue has 1 outstanding TODOs:

• lib/Target/TfheRust/TfheRustEmitter.cpp:706: Share with Verilog Emitter.

This comment was autogenerated by todo-backlinks

[ai-mannamalai]

Take a first attempt at this https://github.com/google/heir/pull/932