Introducing a new FieldCaps ActionFilter

[thalurur]

Issue #, if available:
N/A

Description of changes:
Add a field caps action filter to return only formatted fields for rollup indices

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

Merging #345 (7384ede) into master (0a9b4fb) will decrease coverage by 0.57%.
The diff coverage is 46.57%.

@@             Coverage Diff              @@
##             master     #345      +/-   ##
============================================
- Coverage     75.54%   74.97%   -0.58%     
- Complexity     1333     1347      +14     
============================================
  Files           182      183       +1     
  Lines          6822     6962     +140     
  Branches       1095     1129      +34     
============================================
+ Hits           5154     5220      +66     
- Misses         1071     1142      +71     
- Partials        597      600       +3     

Impacted Files	Coverage Δ	Complexity Δ
...xmanagement/rollup/actionfilter/FieldCapsFilter.kt	44.11% <44.11%> (ø)	15.00 <15.00> (?)
...indexmanagement/rollup/model/RollupFieldMapping.kt	75.00% <50.00%> (-6.82%)	6.00 <1.00> (ø)
...orelasticsearch/indexmanagement/util/IndexUtils.kt	77.14% <80.00%> (+0.21%)	1.00 <0.00> (ø)
...ticsearch/indexmanagement/IndexManagementPlugin.kt	92.10% <100.00%> (+0.06%)	11.00 <1.00> (+1.00)
...arch/indexmanagement/rollup/RollupMapperService.kt	59.25% <100.00%> (-0.21%)	24.00 <2.00> (-1.00)
...nt/indexstatemanagement/model/destination/Slack.kt	40.90% <0.00%> (-13.64%)	2.00% <0.00%> (-2.00%)
...adata/TransportUpdateManagedIndexMetaDataAction.kt	85.18% <0.00%> (-3.71%)	9.00% <0.00%> (-1.00%)
...agement/indexstatemanagement/ManagedIndexRunner.kt	55.04% <0.00%> (-0.62%)	41.00% <0.00%> (ø%)
...csearch/indexmanagement/rollup/util/RollupUtils.kt	77.44% <0.00%> (+1.70%)	0.00% <0.00%> (ø%)
... and 2 more

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[dbbaughe]

Mostly nits or small changes, can address now or later.

Biggest thing is let's start adding some comments to explain the purpose of each part. Can be hard to try and just get a high level view of what's happening (or supposed to happen) as need to read through every function to see what's going on. (This applies to PRs @qreshi and I have too). This can also be done as a follow up though.

[thalurur]

Mostly nits or small changes, can address now or later.

Biggest thing is let's start adding some comments to explain the purpose of each part. Can be hard to try and just get a high level view of what's happening (or supposed to happen) as need to read through every function to see what's going on. (This applies to PRs @qreshi and I have too). This can also be done as a follow up though.

Will do this as a follow up, will add for search interceptor as well in just one PR