Making mesos task healthcheck configurable

[Himavanth]

The configurable parameters are delay, interval, timeout, grace-period
and max-consecutive-failures. More detail on these parameters at
http://mesos.apache.org/documentation/latest/health-checks/

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 #4086 into master will decrease coverage by 5.18%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #4086      +/-   ##
==========================================
- Coverage   86.14%   80.96%   -5.19%     
==========================================
  Files         148      148              
  Lines        7219     7249      +30     
  Branches      438      442       +4     
==========================================
- Hits         6219     5869     -350     
- Misses       1000     1380     +380

Impacted Files	Coverage Δ
...scala/whisk/core/mesos/MesosContainerFactory.scala	61.81% <ø> (ø)	⬆️
...la/src/main/scala/whisk/core/mesos/MesosTask.scala	86.11% <100%> (ø)	⬆️
...core/database/cosmosdb/RxObservableImplicits.scala	0% <0%> (-100%)	⬇️
...core/database/cosmosdb/CosmosDBArtifactStore.scala	0% <0%> (-95.54%)	⬇️
...sk/core/database/cosmosdb/CosmosDBViewMapper.scala	0% <0%> (-92.6%)	⬇️
...whisk/core/database/cosmosdb/CosmosDBSupport.scala	0% <0%> (-83.34%)	⬇️
...abase/cosmosdb/CosmosDBArtifactStoreProvider.scala	0% <0%> (-58.83%)	⬇️
...ain/scala/whisk/core/invoker/InvokerReactive.scala	64.86% <0%> (-16.45%)	⬇️
...la/whisk/core/database/cosmosdb/CosmosDBUtil.scala	92% <0%> (-4%)	⬇️
...cala/whisk/core/containerpool/ContainerProxy.scala	94.02% <0%> (-2.07%)	⬇️
... and 3 more

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[Himavanth]

These changes are merged as part of #4102
So closing this.