Persist Snap logs and allow the user to export them

Currently there's no built-in logging functionality in snap, and it would be great if we could preserve logs from snap in MM, and hence be able to retrieve them by dumping the log file from MM (or by any other ways)

No files, tests, or entry points are named. Start by locating how Snaps currently emit output and how MetaMask stores or exports logs, then clarify the supported log data and retrieval method; done means Snap logs persist in MetaMask and can be exported by the user.

Written by the indexing model from the issue text.