SPIKE: Multithreading in WASM

[jurevans]

We need to investigate whether enabling multithreading in the compiled @namada/shared wasm is cross-browser compatible.

• Can Wasm loaded by Namadillo be set to use multithreading, as we once did in the Chrome extension (via spawning web-workers)?
• If so, will this be cross-browser compatible (Chrome, Firefox, Chrome-based browsers)?

Will add notes from research below:

TBD