In this commit, we move to start requiring the payment addr feature bit
in the invoices we produce. With this change, if a user attempts to pay
one of our invoices (assuming they're also an lnd node), then they'll
receive an error when they attempt to pay. At this point, *most* lnd
nodes should be on v0.11 at this point, and this change will notify any
lagging wallet authors to update, as these payments are generally more
secure.
It's been sometime since we introduced this new safety enhancing feature
bit. At this point, we're now moving to require it as it makes our SCB
recovery system more robust, and it's also an implicit feature bit for
for anchor commitments as they're defined now.
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.
