This avoid restarting the node always with a full radius, which
causes the node the be bombarded with offers which it later has
to delete anyhow.
In order to implement this functionality, several changes were
made as the radius needed to move from the Portal wire protocol
current location to the contentDB and beaconDB, which is
conceptually more correct anyhow.
So radius is now part of the database objects and a handler is
used in the portal wire protocol to access its value.
- Add basic validation for LC bootstrap gossip, validating either
by trusted block root (only 1) when not synced, or by comparing
with the header of the latest finality update when synced.
- Update portal_bridge beacon to also gossip bootstraps into the
network on each end of epoch.
Kim De Mey