More debug options when mode=NUMBA

[jessegrabowski]

Description

• Add a compile flag to write the final numba program to a temp filter on disk, so that fail to compile errors become more readable
• Add a flag to print or write the final codegen string that is actually compiled by numba mode

[ricardoV94]

There are multiple codegens, and some that are just pure python functions that we could print as well. So it should be printout of fgraph + all the inner functions (recursively for inner graphs)