Add API which allows resolving clusters from a given command criterion

[tgianos]

/api/v3/commands/{id}/clusterCiteria/{priority}/clusters will execute the criterion resolution against the clusters in the database to see what would be selected if a job was submitted and evaluated against that criterion

[mprimi]

I'm not in favor of indroducing new API that solves a thin sliver of a problem (but that we will have to maintain or worry about breaking going forward).

It seems to me that this exposes something that we can already kinda do via search APIs.

I'm in favor of introducing API if it solves the whole problem.
In my head, solving this entire problem means

• Take (job) command criteria and (job) cluster criteria
• Expose all steps and intermediate matching result

This is so that when something is not working, we can take a job, run it through this API and have a full debug trace.

[coveralls]

Coverage decreased (-0.002%) to 92.86% when pulling 561f743 on tgianos:GENIE-374 into b9581ee on Netflix:master.

[codecov]

Codecov Report

Merging #956 into master will not change coverage.
The diff coverage is 80%.

@@           Coverage Diff            @@
##             master    #956   +/-   ##
========================================
  Coverage        90%     90%           
- Complexity     3613    3615    +2     
========================================
  Files           439     439           
  Lines         14220   14230   +10     
  Branches        936     937    +1     
========================================
+ Hits          12798   12807    +9     
- Misses         1016    1017    +1     
  Partials        406     406

Impacted Files	Coverage Δ	Complexity Δ
...pis/rest/v3/controllers/CommandRestController.java	85.56% <80%> (-0.32%)	46 <1> (+1)
...services/jpa/JpaClusterPersistenceServiceImpl.java	92.3% <0%> (+0.51%)	58% <0%> (+1%)	⬆️

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[tgianos]

@mprimi I believe you're discussing a different problem than this is targeted at. Your vision for helping to debug execution details is valid and useful but this specific PR is intended for helping administrators more so than end users.

The admins of our deployment asked for the ability to tell which clusters a command can run on and which commands a cluster can use during our meeting last week. I circled back with those admins and asked specifically about this PR and they re-iterated that this seems to solve what they're asking for as they work on the migration from old to new resource resolution mechanisms. Yes, this can partially be addressed with the search API but it is not abstracted in the same manner and isn't as specifically targeted to recreate the environment the clusters are resolved in as this API is.

It builds on existing APIs in the service tier developed for this brand new cluster/command resolution feature so maintenance going forward shouldn't be an issue as it is where we're heading in the near term.

[tgianos]

After discussion on design I'm going to revise this a little bit and open a new PR.