feature: use +100 staging bit for taproot channels

In this commit, we carry out a new notion introduced during a recent
spec meeting to use a feature bit plus 100 before the feature has been
finalized in the spec.

We split into the Final and Staging bits.

feature/default_sets.go

@@ -83,7 +83,7 @@ var defaultSetDesc = setDesc{
 		SetInit:    {}, // I
 		SetNodeAnn: {}, // N
 	},
-	lnwire.SimpleTaprootChannelsOptional: {
+	lnwire.SimpleTaprootChannelsOptionalStaging: {
 		SetInit:    {}, // I
 		SetNodeAnn: {}, // N
 	},

feature/deps.go

@@ -75,7 +75,7 @@ var deps = depDesc{
 	lnwire.ZeroConfOptional: {
 		lnwire.ScidAliasOptional: {},
 	},
-	lnwire.SimpleTaprootChannelsOptional: {
+	lnwire.SimpleTaprootChannelsOptionalStaging: {
 		lnwire.AnchorsZeroFeeHtlcTxOptional: {},
 		lnwire.ExplicitChannelTypeOptional:  {},
 	},

feature/manager.go

@@ -176,8 +176,8 @@ func newManager(cfg Config, desc setDesc) (*Manager, error) {
 			raw.Unset(lnwire.ShutdownAnySegwitRequired)
 		}
 		if cfg.NoTaprootChans {
-			raw.Unset(lnwire.SimpleTaprootChannelsOptional)
-			raw.Unset(lnwire.SimpleTaprootChannelsRequired)
+			raw.Unset(lnwire.SimpleTaprootChannelsOptionalStaging)
+			raw.Unset(lnwire.SimpleTaprootChannelsRequiredStaging)
 		}
 
 		for _, custom := range cfg.CustomFeatures[set] {