Log levels for error reporter

[zenhack]

This has come up a couple times on matrix now: it would be nice to have something like log levels in ErrorReporter; in particular, here are a few things I'd like to be able to filter differently:

• Protocol errors
• Disconnects
• Soon, with 3PH: falling back to using a vine, when forming a direct connection fails

We could go all in and just accept a Logger from the new slog package: https://pkg.go.dev/golang.org/x/exp/slog#Logger

Though I worry this might bloat code size, which I want to avoid for the frontend code in tempest. We could also define an interface with the log levels we care about that Logger satisfies.

[philippgille]

Some related work seems to have been done already: #537

[lthibault]

@philippgille Indeed. I have to go through Ian's PR to see how much of this is covered by the addition of the logging interface. I think this issue might technically be resolved already.