contractcourt+htlcswitch+lnwallet: dynamic commitments

[Crypt-iQ]

Tracking issue for implementing dynamic commitment upgrades as outlined here: Crypt-iQ/bolts@d1a608e

Things that lnd needs:

• lnwire types for the new message types dyn_begin_propose, dyn_propose, dyn_propose_reply, and kickoff_sig
• a state machine similar to the lnwallet/chancloser that handles dynamic commitments by:
  • sending over new taproot funding keys and new csv values via dyn_propose
  • constructing and broadcasting the intermediate kickoff transaction
  • storing data (e.g. propose_height, channel_type, taproot_funding_key, kickoff_feerate) so that a disconnect during negotiation is recoverable
  • validate the received kickoff_sig
• the htlcswitch.ChannelLink needs to be able to:
  • wind down and stop sending / forwarding HTLCs after LND sends dyn_begin_propose
  • validate the commitment_signed and revoke_and_ack messages during the signing phase
  • recover on reconnect via channel_reestablish. This may require some context from the dynamic commitments state machine.
• the contractcourt package needs to:
  • watch for spends from the legacy commitment transaction
  • watch for confirmation of the kickoff transaction
  • watch spends from the kickoff transaction
  • handle anchors fee-bumping of the kickoff transaction

Depends on #6691