Python bindings to QSSC AST/IR

[donjan]

Running qss-compiler 128c937335ce23d35c4e98c3b7618d7420bd11ee

Currently handing off processing to a Python-based program requires writing/reading a text-based MLIR dump. This is clumsy, slow and involves additional parsing. Any parser needs to formally define QSSC-specific dialects.

In the ideal case, the AST/IR tree could be walked from a Python program.

Additional info This issue exists to track the downstream vendor Python stack interaction, and to enable us to post links to someplace. In case this is premature or a better location exists, please notify and close.