Added KMSEncryptPolicy policy template and related test changes

[merzwilliam]

Issue #, if available:
#1186

Description of changes:
Added KMSEncryptPolicy policy template following the similar KMSDecryptPolicy template and updated related tests.

Description of how you validated changes:
Validated via "make pr" command and checking transformed template.

Checklist:

• Write/update tests
• make pr passes
• Update documentation
• Verify transformed template deploys and application functions as expected
• Add/update example to examples/2016-10-31

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

[codecov-io]

Codecov Report

Merging #1192 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1192   +/-   ##
=======================================
  Coverage   94.36%   94.36%           
=======================================
  Files          71       71           
  Lines        3621     3621           
  Branches      713      713           
=======================================
  Hits         3417     3417           
  Misses        104      104           
  Partials      100      100

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[jlhood]

Yay! Thanks for adding this! 😄I went ahead and fixed the merge conflict so this should be good to go!