feat(elasticache): Ensure Redis replication groups have automatic failover enabled

[HugoPBrito]

Context

A check was done to ensure ElastiCache (Redis OSS) replication groups have automatic failover enabled for high availability.

Description

I added a new check elasticache_redis_cluster_automatic_failover_enabled that ensures Elasticache Redis OSS cache clusters use automatic failover to maximize high availability and minimize downtime during failures.

Checklist

• Are there new checks included in this PR? Yes / No
  • If so, do we need to update permissions for the provider? Please review this carefully.
• [x] Review if the code is being covered by tests.
• [x] Review if code is being documented following this specification https://github.com/google/styleguide/blob/gh-pages/pyguide.md#38-comments-and-docstrings

License

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

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 88.93%. Comparing base (b7e2034) to head (7b62c9c). Report is 92 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #4853 +/- ## ========================================== - Coverage 89.20% 88.93% -0.28% ========================================== Files 933 954 +21 Lines 28567 29256 +689 ========================================== + Hits 25483 26018 +535 - Misses 3084 3238 +154 ```

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