channeldb: store close initiator status

This commit adds two new channel statuses which indicate the party that
initatited closing the channel. These statuses are set in conjunction
with the existing commit broadcast status so that we do not need to
migrate existing logic to handle multiple types of closes. This status
is set for locally initiated force closes in this commit because they
follow a similar pattern to cooparative closes, marking the commitment
broadcast then proceeding with tx broadcast. Remote force closes are
added in the following commit, as they are handled differently.

lnwallet/channel.go

@@ -6433,22 +6433,28 @@ func (lc *LightningChannel) MarkBorked() error {
 
 // MarkCommitmentBroadcasted marks the channel as a commitment transaction has
 // been broadcast, either our own or the remote, and we should watch the chain
-// for it to confirm before taking any further action.
-func (lc *LightningChannel) MarkCommitmentBroadcasted(tx *wire.MsgTx) error {
+// for it to confirm before taking any further action. It takes a boolean which
+// indicates whether we initiated the close.
+func (lc *LightningChannel) MarkCommitmentBroadcasted(tx *wire.MsgTx,
+	locallyInitiated bool) error {
+
 	lc.Lock()
 	defer lc.Unlock()
 
-	return lc.channelState.MarkCommitmentBroadcasted(tx)
+	return lc.channelState.MarkCommitmentBroadcasted(tx, locallyInitiated)
 }
 
 // MarkCoopBroadcasted marks the channel as a cooperative close transaction has
 // been broadcast, and that we should watch the chain for it to confirm before
-// taking any further action.
-func (lc *LightningChannel) MarkCoopBroadcasted(tx *wire.MsgTx) error {
+// taking any further action. It takes a locally initiated bool which is true
+// if we initiated the cooperative close.
+func (lc *LightningChannel) MarkCoopBroadcasted(tx *wire.MsgTx,
+	localInitiated bool) error {
+
 	lc.Lock()
 	defer lc.Unlock()
 
-	return lc.channelState.MarkCoopBroadcasted(tx)
+	return lc.channelState.MarkCoopBroadcasted(tx, localInitiated)
 }
 
 // MarkDataLoss marks sets the channel status to LocalDataLoss and stores the