As a follow-on to #1596, which exposes the emscripten FS directly, more useful wrapper could be added to the persistence API.

Some ideas:

• on the JS side, add additional options to loadPyodide to auto-mount a backend
  • the tokens (e.g. pyodide.FS.filesystems.IDBFS) would not yet be avaialble, so it might have to be by name
  • it might be unclear how to persist data back out, but a naive polling solution would work
• on the python side, offer a some context managers, etc. that would wrap up the lifecycle of:
  • mount, syncfs(true), do some stuff, syncfs(false)

reporters note: i'm not signing up to implement these, necessarily, but we'd prefer to land things directly here, rather in my downstream of interest, jupyterlite, if others are interested in this...