multi: use new revocation log when creating breach retribution

This commit changes the `NewBreachRetribution` to use the new revocation
log format, while maintaining the compatibilty to use an older
revocation log format. Unit tests have been added to make sure a breach
retribution can be created in both log formats.

This also means the watch tower needs to pass the relevant commit tx at
its backup height when creating the breach retribution during backing
up. This is achieved by recording the current remote commitment state
before advancing the remote commitment chain.

contractcourt/chain_watcher.go

@@ -794,6 +794,7 @@ func (c *chainWatcher) handlePossibleBreach(commitSpend *chainntnfs.SpendDetail,
 	spendHeight := uint32(commitSpend.SpendingHeight)
 	retribution, err := lnwallet.NewBreachRetribution(
 		c.cfg.chanState, broadcastStateNum, spendHeight,
+		commitSpend.SpendingTx,
 	)
 
 	switch {