Adding RestActions support for Start/Stop Detector API

[saratvemulapalli]

*Issue #195 *

Description of changes:
Adding RestActions support for Start/Stop Detector API which is needed to support AD FGAC

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[codecov]

Codecov Report

Merging #244 into master will increase coverage by 0.44%.
The diff coverage is 53.73%.

@@             Coverage Diff              @@
##             master     #244      +/-   ##
============================================
+ Coverage     71.70%   72.15%   +0.44%     
- Complexity     1368     1387      +19     
============================================
  Files           157      160       +3     
  Lines          6513     6582      +69     
  Branches        493      495       +2     
============================================
+ Hits           4670     4749      +79     
+ Misses         1611     1599      -12     
- Partials        232      234       +2     

Flag	Coverage Δ	Complexity Δ
#cli	79.27% <ø> (ø)	0.00 <ø> (ø)
#plugin	71.27% <53.73%> (+0.51%)	1387.00 <18.00> (+19.00)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ	Complexity Δ
.../handler/IndexAnomalyDetectorJobActionHandler.java	11.65% <10.00%> (+11.65%)	4.00 <1.00> (+4.00)
...icsearch/ad/rest/RestAnomalyDetectorJobAction.java	50.00% <14.28%> (+10.00%)	3.00 <1.00> (ø)
...earch/ad/transport/AnomalyDetectorJobResponse.java	75.00% <75.00%> (ø)	4.00 <4.00> (?)
...d/transport/AnomalyDetectorJobTransportAction.java	86.36% <86.36%> (ø)	3.00 <3.00> (?)
...search/ad/transport/AnomalyDetectorJobRequest.java	95.65% <95.65%> (ø)	7.00 <7.00> (?)
...stroforelasticsearch/ad/AnomalyDetectorPlugin.java	93.54% <100.00%> (ø)	10.00 <0.00> (ø)
...csearch/ad/transport/AnomalyDetectorJobAction.java	100.00% <100.00%> (ø)	2.00 <2.00> (?)
...ransport/DeleteAnomalyDetectorTransportAction.java	54.21% <0.00%> (-4.82%)	15.00% <0.00%> (-1.00%)
... and 3 more

[ohltyler]

LGTM!

[ylwu-amzn]

LGTM. Thanks for the change!