* SubscriptionService tracks shard and content topic interest
* Emit MessageReceivedEvent on subscribed content topics
* Add selectPeers() to PeerManager for future edge node sub impl
* Add test_api_subscriptions.nim with a placeholder sub test
* introduce createNode
# Conflicts:
# apps/wakunode2/cli_args.nim
* remove confutils dependency on the library
* test: remove websocket in default test config
* update to latest specs
* test: cli_args
* align to spec changes (sovereign, message conf, entrypoints
* accept enr, entree and multiaddr as entry points
* post rebase
* format
* change from "sovereign" to "core"
* add example
* get example to continue running
* nitpicks
* idiomatic constructors
* fix enum naming
* replace procs with consts
* remove messageConfirmation
* use pure enum
* rename example file