* misc/metrics: Explicitly delegate event recording to each recorder
This allows delegating a single event to multiple `Recorder`s. That enables e.g. the
`identify::Metrics` `Recorder` to act both on `IdentifyEvent` and `SwarmEvent`. The latter enables
it to garbage collect per peer data on disconnects.
* protocols/dcutr: Expose PROTOCOL_NAME
* protocols/identify: Expose PROTOCOL_NAME and PUSH_PROTOCOL_NAME
* protocols/ping: Expose PROTOCOL_NAME
* protocols/relay: Expose HOP_PROTOCOL_NAME and STOP_PROTOCOL_NAME
* misc/metrics: Track # connected nodes supporting specific protocol
An example metric exposed with this patch:
```
libp2p_identify_protocols{protocol="/ipfs/ping/1.0.0"} 10
```
This implies that 10 of the currently connected nodes support the ping protocol.
Rename `KademliaEvent::InboundRequestServed` to `KademliaEvent::InboundRequest` and move
`InboundPutRecordRequest` into `InboundRequest::PutRecord` and `InboundAddProviderRequest` into
`InboundRequest::AddProvider`.
Co-authored-by: supercmmetry <vishaals2000@gmail.com>
Probability for a Kademlia query to return in less than 100 milliseconds
is low, thus increasing the lower bucket to improve accuracy within the
higher ranges.
