Add RBF-bumping of justice txn, given they are only signed by us we
can RBF at wish.
Aggregation of bump-candidates and more aggresive bumping heuristics
are left open
Fix tests broken by introduction of more txn broadcast.
Some tests may have a relaxed check (claim_htlc_ouputs_single_tx)
as broadcast bumped txn are now interwining in previous broadcast ones
and breaking simple expectations
Use bumping engine to rebuild claiming transaction in case of partial-
claim of its outpoints set.
Adding this struct will allow us to remove the circular reference
between ChainListeners and the ChainWatchInterface, because it
separates out the responsibility of notifying listeners about new
blocks from the responsibility of storing and retrieving watched
transactions.
This includes the purpose of this PR, which is to remove the circular reference created by ChainListeners self-adding themselves to their ChainWatchInterface's `listeners` field.
