A sidecar channel uses different multisig keys than a normal order so we
need to fix the lookup in the batch transaction. While we're at it, we
might as well return the self chan balance and whether it was a sidecar
channel in the leases response.
In preparation for loading the full local pending batch snapshot instead
of only the ID when starting the daemon, we add a new function to the
database to retrieve the snapshot.
In this commit, we add a new key within the order bucket that stores
just the node tier for a given order. The current code only _expects_ a
node tier to exist for Bid orders, however things have been designed
such that, we can easily add tier options for Ask orders as well.
Along the way we modify the `orderCallback` to include the node tier
information as its read from a distinct bucket. In the future, we'll
likely want to make this into a struct so the function signature doesn't
ever expand.
