Add support for Elasticache ReplicationGroup

[j-fulbright]

Currently the provider only supports Global Datastore and Serverless cache, but it needs to also support ReplicationGroup (like the regular AWS provider supports). Neither of the included classes expose the necessary functionality that I would expect

[corymhall]

@j-fulbright this provider is generated from AWS Cloud Control. Until Cloud Control supports this resource we recommend using the AWS Provider resources.

[j-fulbright]

Thanks @corymhall ! I was a bit shocked it was missing so many of the Resources, but that makes sense that its not even there in AWS.