Updates #5435
Based on the discussion in #5435, we can better support transactional data models
by making the underlying storage layer a parameter (which can be specialized for
the request) rather than a long-lived member of Authority.
Now that Authority is just an instantaneous snapshot of state, we can do things
like provide idempotent methods and make it cloneable, too.
Signed-off-by: Tom DNetto <tom@tailscale.com>
This PR implements the synchronization mechanics for TKA: generating a SyncOffer, processing a SyncOffer to find an intersection,
and computing the set of AUMs that should be transmitted to effect convergence.
This is the final PR implementing core mechanics for TKA.
Signed-off-by: Tom DNetto <tom@tailscale.com>
