+eventStream introduce a better, more debuggable way to use eventStream

[ktoso]

Improve debug information from subscribing to event stream.

Aiming to debug why on CI this sometimes lost an event: ClusterSingletonPluginClusteredTests.test_singleton_lifecycle

[ktoso]

This results in such improved information about stream subscribers:

[captured] [first] [2022-10-27 14:19:08.3220] [ClusterEventStream.swift:240][/system/clusterEventStream] [trace] Published event membershipChange(sact://first@127.0.0.1:7111 :: [unknown] -> [joining]) to 4 subscribers and 3 async subscribers
[captured] [first] // "actor/id": /system/clusterEventStream
[captured] [first] // "eventStream/asyncSubscribers":
[captured] [first] //   SubscriberID(oid: ObjectIdentifier(0x0000600000604240), loc: DistributedCluster/OperationLogDistributedReceptionist.swift:260)
[captured] [first] //   SubscriberID(oid: ObjectIdentifier(0x000060000061bd80), loc: DistributedCluster/DowningStrategy.swift:98)
[captured] [first] //   SubscriberID(oid: ObjectIdentifier(0x000060000061bd60), loc: DistributedCluster/ClusterSingletonBoss.swift:94)
[captured] [first] // "eventStream/event": DistributedCluster.Cluster.Event.membershipChange(sact://first@127.0.0.1:7111 :: [unknown] -> [joining])

Heh of course now it passed ;)