Track rebalances, and report income events for them.
Previously `listincome` would report:
- invoice event, debit, outgoing channel
- invoice_fee event, debit, outgoing channel
- invoice event, credit, inbound channel
Now reports:
- rebalance_fee, debit, outgoing channel
(same value as invoice_fee above)
Note: only applies on channel events; if a rebalance falls to chain
we'll use the older style of accounting.
Changelog-None
Adds schema definitions and manpages for bkpr- commands; also renames
the commands to all start with 'bkpr-', so they're easier to identify/
make runes about.