[testing] Implement cli tool to generate llvm IR for kernels without running them

[ZzEeKkAa]

We want something like dpexcli compile -m <python module path> -n <kernel function name> -o <llvm output path> to generate llvm code of function without running it.

TODO:

• think about passing arguments type

[diptorupd]

@ZzEeKkAa take a look at https://github.com/IntelPython/numba-dpex/blob/8fc7fbddb2b73d80b98a0e629fddb6647aa456f8/numba_dpex/tests/experimental/codegen/test_intenum_literal_codegen.py#L15.

It is possible to only compile a kernel provided we generate the right signature. Perhaps a solution can be to have a CLI tool that takes a config file to spell out the signature and any extra compile flags.