lnwallet: update HTLC script generation to account for new covenant HTLC's
lnwallet: update HTLC script generation to account for new covenant HTLC's

This commit updates the set of functions tasked with generating HTLC’s
scripts for new commitments to now adhere to the new commitment
transaction design. With this change, the process of claiming an HTLC
now requires a second-level HTLC transaction, which solves a prior
issues due to the tight coupling of the timeout and delay clauses when
claiming an HTLC.

aakselrod/lnd,LightningNetwork/lnd,aakselrod/lnd,AndrewSamokhvalov/lnd,AndrewSamokhvalov/lnd,LightningNetwork/lnd,ddustin/lnd,ddustin/lnd