lnwallet: revamp restoring channel state from disk after a restart
lnwallet: revamp restoring channel state from disk after a restart

In this commit we complexly revamp the process of restoring all channel
state back into memory after a restart. We’ll now properly do the
following: restore the pending “dangling” commit of the remote party
into the in-memory commitment chain, re-populate all active HTLC’s back
into their respective update logs with the proper indexes/counters, and
properly restore the current commitment of the remote party back in
memory.

LightningNetwork/lnd,LightningNetwork/lnd,aakselrod/lnd,aakselrod/lnd