Python/py2wasm PoC

[carlpulley-da]

Python/py2wasm WebAssembly Integration PoC

This is sadly a failed experiment!

• py2wasm has no current ability for an engineer to say which functions should be imported or exported
  • to work around this limitation, we need to use py2wasm to compile to the C source code, monkey patch the generated C sources and then use py2wasm` to generate the WASM binary code
• py2wasm assumes that a wasmer runtime is present, and this in turn requires that a large number of host functions need to be defined (some of which should definitely not be used within a Canton participant setting)

Note: this PR uses the docker environment built by https://github.com/carlpulley-da/py2wasm-docker