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.
