Handle template parameters

[tim-hoffman]

The following test cases end with an error like: Failed to generate LLZK IR: variable N not found:

loops/fib_template.circom
loops/for_known.circom
loops/inner_conditional_01.circom
loops/inner_conditional_03.circom
loops/inner_loop_07.circom
loops/inner_loop_08.circom

In llzk_backend/src/module.rs, need to generate poly.read_const for each name in struct_params in both FunctionContext instances (for compute and constrain functions), being sure the Value for the named variable (technically constant in this case) gets added to the block context stack variable tracker.

It looks like the poly dialect is not yet supported in llzk-rs so that should be handled first.