Update CloudWatch Alarm exlusive and only one definitions

[kddejong]

Issue #, if available:
Fix #766
Description of changes:

• Sort Exclusive and OnlyOne json docs
• Update OnlyOne for CloudWatch Alarm to require MetricName or Metrics
• Update Exclusive for CloudWatch Alarm to have when Metrics are specified that Namespace, Dimensions, and Period are not defined

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[kddejong]

When dropping Metrics, Statistics, and ExtendedStatistic you will get this error. MetricName must not be null (Service: AmazonCloudWatch; Status Code: 400; Error Code: ValidationError; ...) so Updated the definition as needed for OnlyOne.

From https://docs.aws.amazon.com/AmazonCloudWatch/latest/APIReference/API_PutMetricAlarm.html
there is also this.

If you use the Metrics parameter, you cannot include the MetricName, Dimensions, Period, Namespace, Statistic, or ExtendedStatistic parameters of PutMetricAlarm in the same operation. Instead, you retrieve the metrics you are using in your math expression as part of the Metrics array.

[codecov]

Codecov Report

Merging #771 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #771   +/-   ##
=======================================
  Coverage   85.54%   85.54%           
=======================================
  Files         121      121           
  Lines        7084     7084           
  Branches     1702     1702           
=======================================
  Hits         6060     6060           
  Misses        638      638           
  Partials      386      386

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[cmmeyer]

Seems reasonable. Do the test fixtures need to be modified to include these cases?

[cmmeyer]

At the very least it looks like this impacts the number of expected failures in the unit tests:

AssertionError: Expected 57 failures, got 63 on test/fixtures/templates/quickstart/cis_benchmark.yaml