This commit adds CrdsEntry trait which allows generic lookups into crds
table. For example to get ContactInfo or LowestSlot associated with a
Pubkey, the lookup code would be respectively:
crds.get::<&ContactInfo>(pubkey)
crds.get::<&LowestSlot>(pubkey)
push_lowest_slot cannot sign the new crds-value unless the id (pubkey)
argument passed-in is the same pubkey as in ClusterInfo::keypair(), in
which case the id argument is redundant:
https://github.com/solana-labs/solana/blob/bb41cf346/gossip/src/cluster_info.rs#L824-L845
Additionally, the lookup is done with self.id(), but insert is done with
the id argument, which is logically a bug.
* Move gossip modules to solana-gossip
* Update Protocol abi digest due to move
* Move gossip benches and hook up CI
* Remove unneeded Result entries
* Single use statements