We will use this and its following commits to break the original
`Resolve` methods into two parts - the first part is moved to a new
method `Launch`, which handles sending a sweep request to the sweeper.
The second part remains in `Resolve`, which is mainly waiting for a
spending tx.
Breach resolver currently doesn't do anything in its `Launch` since the
sweeping of justice outputs are not handled by the sweeper yet.
This `immediate` flag was added as a hack so during a restart, the
pending resolvers would offer the inputs to the sweeper and ask it to
sweep them immediately. This is no longer need due to `blockbeat`, as
now during restart, a block is always sent to all subsystems via the
flow `ChainArb` -> `ChannelArb` -> resolvers -> sweeper. Thus, when
there are pending inputs offered, they will be processed by the sweeper
immediately.
Since we have two other examples of XArbitrator, we rename
BreachArbiter to BreachArbitrator to keep things consistent.
The aim is to reduce the amount of lore you need to know to
intuit where things are or what they do.
