improve libp2p connected peer metrics

[jxs]

Issue Addressed

submits #4870 reworked with #5265 addressed:

• maintained the libp2p_peers_connected metric as its standard
• added PEERS_CONNECTED_MULTI which contains the sum of all the peers connected as an IntGaugeVec which means it descriminates per direction and transport
• removed NETWORK_INBOUND_PEERS and NETWORK_INBOUND_PEERS as they are covered by PEERS_CONNECTED_MULTI and are not standard
• modified DISCOVERY_BYTES which gathers all the transferred discovery bytes which can be discriminated by outbound and inbound.
• removed DISCOVERY_SENT_BYTES and DISCOVERY_RECV_BYTES as they are covered by DISCOVERY_BYTES
• removed update_connected_peer_metrics function, we increment and decrement the number of peers on PeerManager NetworkBehaviour's FromSwarm::ConnectionEstablished and FromSwarm::ConnectionClosed events, and PEERS_PER_CLIENT is already updated when we identify a client.

[AgeManning]

Have we run these changes?

We've switched from setting the gauges for connected to peers to solely relying on increment and decrement. I'm worried there's a thousand edge-cases where peers disconnect/connect and we don't account for them putting these metrics off.

If the peer-count metric is off, it will be something we'll need to fix urgently.

[AgeManning]

@Mergifyio queue

[mergify]

queue

✅ The pull request has been merged automatically

The pull request has been merged automatically at a89ff10