Add prefix for topics

[ningyougang]

Description

This pr's target is, add prefix for all topics and add extra prefix for userEvent topic only.
After applied this pr, some zones(e.g. test1, test2, test3) can share same kafka instance using different prefix topic,
BTW, userEvent is special, user may want to send some zones's event to same topic, so added extra prefix for it, user can decide whether want to send the event to same topic or different topic.

I tested in my local env

• Default configuration (all topics's prefix is empty string), topics name as below
  

• kafka_topics_prefix: "blue_" and kafka_topics_userEvent_prefix: "test_"
  

And the activations are successful on above 2 cases both.

Related issue and scope

• I opened an issue to propose and discuss this change (#????)

My changes affect the following components

• API
• Controller
• Message Bus (e.g., Kafka)
• Loadbalancer
• Invoker
• Intrinsic actions (e.g., sequences, conductors)
• Data stores (e.g., CouchDB)
• Tests
• Deployment
• CLI
• General tooling
• Documentation

Types of changes

• Bug fix (generally a non-breaking change which closes an issue).
• Enhancement or new feature (adds new functionality).
• Breaking change (a bug fix or enhancement which changes existing behavior).

Checklist:

• I signed an Apache CLA.
• I reviewed the style guides and followed the recommendations (Travis CI will check :).
• I added tests to cover my changes.
• My changes require further changes to the documentation.
• I updated the documentation where necessary.

[codecov-io]

Codecov Report

Merging #5062 (eb2e900) into master (1753946) will decrease coverage by 6.92%.
The diff coverage is 53.33%.

@@            Coverage Diff             @@
##           master    #5062      +/-   ##
==========================================
- Coverage   82.80%   75.88%   -6.93%     
==========================================
  Files         207      207              
  Lines       10034    10047      +13     
  Branches      444      418      -26     
==========================================
- Hits         8309     7624     -685     
- Misses       1725     2423     +698     

Impacted Files	Coverage Δ
...rg/apache/openwhisk/core/scheduler/Scheduler.scala	0.00% <0.00%> (ø)
.../apache/openwhisk/core/controller/Controller.scala	55.66% <33.33%> (+0.85%)	⬆️
...scala/org/apache/openwhisk/common/UserEvents.scala	75.00% <50.00%> (+8.33%)	⬆️
.../scala/org/apache/openwhisk/core/WhiskConfig.scala	95.36% <100.00%> (+0.06%)	⬆️
...apache/openwhisk/core/ack/MessagingActiveAck.scala	58.33% <100.00%> (+3.78%)	⬆️
...nwhisk/core/database/RemoteCacheInvalidation.scala	80.64% <100.00%> (+0.64%)	⬆️
...enwhisk/core/loadBalancer/CommonLoadBalancer.scala	72.56% <100.00%> (ø)
...che/openwhisk/core/loadBalancer/LoadBalancer.scala	76.92% <100.00%> (ø)
...e/loadBalancer/ShardingContainerPoolBalancer.scala	80.79% <100.00%> (ø)
...la/org/apache/openwhisk/core/invoker/Invoker.scala	70.31% <100.00%> (+0.47%)	⬆️
... and 21 more

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[style95]

LGTM

[bdoyle0182]

LGTM

[codecov-commenter]

Codecov Report

Merging #5062 (1b73098) into master (f7ec9e3) will increase coverage by 35.84%.
The diff coverage is 53.33%.

@@             Coverage Diff             @@
##           master    #5062       +/-   ##
===========================================
+ Coverage   38.79%   74.63%   +35.84%     
===========================================
  Files         218      220        +2     
  Lines       10700    10822      +122     
  Branches      454      445        -9     
===========================================
+ Hits         4151     8077     +3926     
+ Misses       6549     2745     -3804     

Impacted Files	Coverage Δ
...rg/apache/openwhisk/core/scheduler/Scheduler.scala	0.00% <0.00%> (ø)
.../apache/openwhisk/core/controller/Controller.scala	55.66% <33.33%> (+55.66%)	⬆️
...scala/org/apache/openwhisk/common/UserEvents.scala	75.00% <50.00%> (+8.33%)	⬆️
...la/org/apache/openwhisk/core/invoker/Invoker.scala	46.93% <66.66%> (-22.91%)	⬇️
.../scala/org/apache/openwhisk/core/WhiskConfig.scala	95.54% <100.00%> (+0.05%)	⬆️
...apache/openwhisk/core/ack/MessagingActiveAck.scala	58.33% <100.00%> (+3.78%)	⬆️
...nwhisk/core/database/RemoteCacheInvalidation.scala	80.64% <100.00%> (+0.64%)	⬆️
...enwhisk/core/loadBalancer/CommonLoadBalancer.scala	72.56% <100.00%> (+72.56%)	⬆️
...che/openwhisk/core/loadBalancer/LoadBalancer.scala	76.92% <100.00%> (+76.92%)	⬆️
...e/loadBalancer/ShardingContainerPoolBalancer.scala	80.79% <100.00%> (+80.79%)	⬆️
... and 136 more

---

Continue to review full report at Codecov.

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Δ = absolute <relative> (impact), ø = not affected, ? = missing data
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