## Issue Addressed
Potentially resolves#1647 and sync stalls.
## Proposed Changes
The handling of the state of banned peers was inadequate for the complex peerdb data structure. We store a limited number of disconnected and banned peers in the db. We were not tracking intermediate "disconnecting" states and the in some circumstances we were updating the peer state without informing the peerdb. This lead to a number of inconsistencies in the peer state.
Further, the peer manager could ban a peer changing a peer's state from being connected to banned. In this circumstance, if the peer then disconnected, we didn't inform the application layer, which lead to applications like sync not being informed of a peers disconnection. This could lead to sync stalling and having to require a lighthouse restart.
Improved handling for peer states and interactions with the peerdb is made in this PR.
66f0cf4430