fix: sharder should use peer identity from Peers package

[VinozzZ]

Which problem is this PR solving?

DeterministicSharder wasn't updated to use the new peer identification system to determine which peer a given trace belongs to. This resulted Refinery couldn't identify itself in the peer list within the sharding system.

Short description of the changes

• Consolidate and unify code for retrieving peer identity
• replace : with | as the delimiter in stress relief message
• make sure filepeer returns PeerListenAddr as its public address

[kentquirk]

I think this looks fine. I am realizing, though, that FilePeers is now almost pointless, because its main reason for existing for more than one node is so that someone can avoid running Redis. But now we depend on Redis for more than just peers, so even if you do FilePeers you still have to do Redis.

[VinozzZ]

I think this looks fine. I am realizing, though, that FilePeers is now almost pointless, because its main reason for existing for more than one node is so that someone can avoid running Redis. But now we depend on Redis for more than just peers, so even if you do FilePeers you still have to do Redis.

The other place that depends on Redis is stress relief and configs. Using filepeer means, peers will act independently in both stress relief and config change system. Essentially, if a Refinery cluster is using filepeer, they won't get much benefit from this release. We can document it, but at least it's not breaking existing behavior.