Add policy for EventBridge putEvents

[Russ-K]

Issue #, if available:
#1187

Description of changes:
Added a policy for EventBridge putEvents.
This supports putting events for all event buses at this time.

Description of how you validated changes:

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 #1203 into develop will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop    #1203   +/-   ##
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  Coverage    94.33%   94.33%           
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  Files           72       72           
  Lines         3725     3725           
  Branches       733      733           
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  Hits          3514     3514           
  Misses         107      107           
  Partials       104      104

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[jlhood]

Actually, after discussing internally, we're going to put this policy template on hold in case the EventBridge team adds support for per-event bus permissions on PutEvents. See #1187 (comment). Sorry for the back and forth on this!