[ISSUE #989] consumer and producer client add unit support (WithUnitName)

[twz915]

What is the purpose of the change

#989

Support unit producer/consumer.
Supports consuming messages from Unit2 in Unit1

rocketmq.NewPushConsumer(
	consumer.WithGroupName(s.GroupID),
	consumer.WithNameServerDomain(s.NameServerURL),
	consumer.WithUnitName("unsh"),
	consumer.WithInstanceName("unsh"),
	...
)


rocketmq.NewProducer(
	producer.WithGroupName(s.GroupID),
	producer.WithNameServerDomain(s.NameServerURL),
	producer.WithUnitName("unsh"),
	producer.WithInstanceName("unsh"),
	...
)

[codecov-commenter]

Codecov Report

Merging #988 (3a92798) into master (896a8a3) will decrease coverage by 0.07%.
The diff coverage is 15.15%.

@@            Coverage Diff             @@
##           master     #988      +/-   ##
==========================================
- Coverage   23.32%   23.26%   -0.07%     
==========================================
  Files          52       52              
  Lines        7266     7294      +28     
==========================================
+ Hits         1695     1697       +2     
- Misses       5339     5363      +24     
- Partials      232      234       +2     

Impacted Files	Coverage Δ
consumer/option.go	18.18% <0.00%> (-1.66%)	⬇️
producer/option.go	32.87% <0.00%> (-5.84%)	⬇️
primitive/nsresolver.go	53.09% <55.55%> (-1.11%)	⬇️

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