Move most logs in the chain module to the debug level

[tankyleo]

When the node is idle, the info level was quite spammy. It is now quiet.

[ldk-reviews-bot]

👋 Thanks for assigning @benthecarman as a reviewer!
I'll wait for their review and will help manage the review process.
Once they submit their review, I'll check if a second reviewer would be helpful.

[benthecarman]

lgtm, however might be useful to just have a single info log that says each time a sync happens.

[tankyleo]

lgtm, however might be useful to just have a single info log that says each time a sync happens.

My intention is to avoid periodic information logs at the info level. I want to let the node sit for a week, and if nothing happened, no issues, nothing out of the ordinary, then no logs :)

Maybe I could just watch Warn and Error, but if I am generating an address for example, or connecting to a peer / opening a channel, that should be an info, not a warn. And I won't want these events to be hidden among the many "sync happened" logs over a week.

[tnull]

Hmm, not super opposed to these concrete changes, but in general we should expose more actionable information on INFO and DEBUG levels, as currently it's hardly exposing any information on INFO.

FWIW, as recently mentioned we should rework the log-level concept across crates at some point (soon), then maybe also tackling or closing #481 for instance.

Anyways, going ahead and landing this for now, mostly as we currently assume (and default to) users running on DEBUG anyways.