Merge accumulated changes related to message queue (#5098)
* balance partitions on brokers
* prepare topic partition first and then publish, move partition
* purge unused APIs
* clean up
* adjust logs
* add BalanceTopics() grpc API
* configure topic
* configure topic command
* refactor
* repair missing partitions
* sequence of operations to ensure ordering
* proto to close publishers and consumers
* rename file
* topic partition versioned by unixTimeNs
* create local topic partition
* close publishers
* randomize the client name
* wait until no publishers
* logs
* close stop publisher channel
* send last ack
* comments
* comment
* comments
* support list of brokers
* add cli options
* Update .gitignore
* logs
* return io.eof directly
* refactor
* optionally create topic
* refactoring
* detect consumer disconnection
* sub client wait for more messages
* subscribe by time stamp
* rename
* rename to sub_balancer
* rename
* adjust comments
* rename
* fix compilation
* rename
* rename
* SubscriberToSubCoordinator
* sticky rebalance
* go fmt
* add tests
* balance partitions on brokers
* prepare topic partition first and then publish, move partition
* purge unused APIs
* clean up
* adjust logs
* add BalanceTopics() grpc API
* configure topic
* configure topic command
* refactor
* repair missing partitions
* sequence of operations to ensure ordering
* proto to close publishers and consumers
* rename file
* topic partition versioned by unixTimeNs
* create local topic partition
* close publishers
* randomize the client name
* wait until no publishers
* logs
* close stop publisher channel
* send last ack
* comments
* comment
* comments
* support list of brokers
* add cli options
* Update .gitignore
* logs
* return io.eof directly
* refactor
* optionally create topic
* refactoring
* detect consumer disconnection
* sub client wait for more messages
* subscribe by time stamp
* rename
* rename to sub_balancer
* rename
* adjust comments
* rename
* fix compilation
* rename
* rename
* SubscriberToSubCoordinator
* sticky rebalance
* go fmt
* add tests
* tracking topic=>broker
* merge
* comment
Chris Lu