Accumulated changes for message queue (#6600)

* rename

* set agent address

* refactor

* add agent sub

* pub messages

* grpc new client

* can publish records via agent

* send init message with session id

* fmt

* check cancelled request while waiting

* use sessionId

* handle possible nil stream

* subscriber process messages

* separate debug port

* use atomic int64

* less logs

* minor

* skip io.EOF

* rename

* remove unused

* use saved offsets

* do not reuse session, since always session id is new after restart

remove last active ts from SessionEntry

* simplify printing

* purge unused

* just proxy the subscription, skipping the session step

* adjust offset types

* subscribe offset type and possible value

* start after the known tsns

* avoid wrongly set startPosition

* move

* remove

* refactor

* typo

* fix

* fix changed path

weed/command/command.go

@@ -32,6 +32,7 @@ var Commands = []*Command{
 	cmdMaster,
 	cmdMasterFollower,
 	cmdMount,
+	cmdMqAgent,
 	cmdMqBroker,
 	cmdS3,
 	cmdScaffold,