Add emscripten build of `csp` for webassembly

[timkpaine]

This will be tricky given our use of threading, our various external adapters, reliance on filesystem, etc etc.

[timkpaine]

C++ Adapter dependencies:

• Arrow/Parquet: https://github.com/apache/arrow/pull/35672
• ~~Kafka~~ should be completely disabled

Python Adapter dependencies:

• DB: ? should be fine as its just SQLAlchemy
• CSV: should work fine against browser storage
• perspective: going to be reworked
• websocket: webserver, won't work
• Symphony: disabled when dep is missing
• Slack: disabled when dep is missing

[timkpaine]

https://cibuildwheel.pypa.io/en/stable/setup/#pyodide-webassembly-builds-experimental