This defines the zero-conf feature bit, the scid-alias feature bit,
the zero-conf channel type, and the scid-alias channel type. It also
defines the dependency "tree" that exists for the feature bits.
The scid-alias feature bit signals that the node requires an alias
short channel id to be sent in funding_locked. The scid-alias channel
type requires that the channel is private, in addition to some other
forwarding-related privacy measures.
This fixes an issue where if one tries to unset a feature like anchors,
and other feature depend on it, then `lnd` fails to start as it realizes
that its dependnacy set is inconsistent.
Fixes https://github.com/lightningnetwork/lnd/issues/6002
This commit introduces a feature.Manager, which derives feature vectors
for various contexts within the daemon. The sets can be described via a
staticly compiled format, which makes any runtime adjustments to the
feature sets when the manager is initialized.
