actionify change policy API

[bowenlan-amzn]

Issue #, if available:
#292

Description of changes:
actionify add policy API, refactor our API code so we have an action name to each API

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 #303 into master will increase coverage by 0.04%.
The diff coverage is 79.73%.

@@             Coverage Diff              @@
##             master     #303      +/-   ##
============================================
+ Coverage     74.91%   74.95%   +0.04%     
- Complexity      755      769      +14     
============================================
  Files           105      108       +3     
  Lines          4102     4145      +43     
  Branches        640      642       +2     
============================================
+ Hits           3073     3107      +34     
- Misses          692      699       +7     
- Partials        337      339       +2     

Impacted Files	Coverage Δ	Complexity Δ
...temanagement/transport/action/ISMStatusResponse.kt	93.33% <ø> (ø)	6.00 <0.00> (ø)
...ransport/action/changepolicy/ChangePolicyAction.kt	66.66% <66.66%> (ø)	2.00 <2.00> (?)
...action/changepolicy/TransportChangePolicyAction.kt	76.52% <76.52%> (ø)	4.00 <4.00> (?)
...ansport/action/changepolicy/ChangePolicyRequest.kt	86.66% <86.66%> (ø)	6.00 <6.00> (?)
...agement/indexstatemanagement/model/ChangePolicy.kt	90.47% <88.88%> (-0.44%)	8.00 <2.00> (+2.00)	⬇️
...ticsearch/indexmanagement/IndexManagementPlugin.kt	91.17% <100.00%> (+0.13%)	9.00 <0.00> (ø)
...nagement/indexstatemanagement/model/StateFilter.kt	75.00% <100.00%> (+8.33%)	3.00 <3.00> (+2.00)
...temanagement/resthandler/RestChangePolicyAction.kt	93.33% <100.00%> (+11.12%)	6.00 <1.00> (-1.00)	⬆️
...xstatemanagement/resthandler/AsyncActionHandler.kt	50.00% <0.00%> (-50.00%)	1.00% <0.00%> (-1.00%)
... and 3 more

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[dbbaughe]

Did this not work? client.get(getRequest, ActionListener.wrap(::onGetPolicyResponse, ::onFailure))