Store the server's static loop-in confirmation-risk decision and the time it
was received. This lets recovered swaps reconstruct whether payment waiting had
already started and how much of the payment timeout remains.
Wire notification handling to persist accepted and rejected decisions before
caching and forwarding them. If the swap row is not present yet, the
notification is still cached so the per-swap waiter can replay and store the
decision later.
Recover accepted decisions by starting the payment deadline from the persisted
decision time, and recover rejected decisions by canceling the invoice and
failing the swap instead of waiting forever.
Added option WithSkippedTxns, which has one historical problematic tx by default.
Sweeps originating from these transactions are omitted when reading from DB.
loopdb: add column sweep_batches.cancelled and replaced DropBatch with
CancelBatch. It is needed, because sweep.batch_id is a foreign key to batch.
Changed StoreMock.InsertSweepBatch not to reuse batch_id. This is needed by
the test, which checks that new batch has fresh ID.
SwapHash used to be a key in the sweeps table. Now the key is outpoint which
replaces columns outpoint_txid and outpoint_index. In-memory structures and unit
tests were also updated to use outpoint as key. Outpoint is truly unique.
This data is not used by Batcher since commit
"sweepbatcher: load swap from loopdb, not own store".
Now sweepbatcher.Store depends only on tables sweeps and sweep_batches
and does not depend on swaps, loopout_swaps and htlc_keys, making it
easier to reuse.
