fix: Use AWS::Partition Pseudo Parameter in IAM ARNs

[kentquirk]

Which problem is this PR solving?

In AWS GovCloud, the RDS and CloudWatch Logs templates fail because the RDS and CloudWatch Logs templates contain IAM ARNs hardcoded with the AWS commercial partition (aws) instead of (aws-us-gov).

Example Error Message:

waiting for CloudFormation Stack (arn:aws-us-gov:cloudformation:us-gov-west-1:<redacted>) create: stack status (ROLLBACK_COMPLETE): The following resource(s) failed to create: [LogSubscription]. Rollback requested by user.
    	
    Resource handler returned message: "Invalid request provided: AWS::Logs::SubscriptionFilter. Could not deliver test message to specified Firehose stream. Check if the given Firehose stream is in ACTIVE state. (Service: CloudWatchLogs, Status Code: 400, Request ID: 123abc)" (RequestToken: 1fc17137-260a-91fe-803f-75e5cce376c2, HandlerErrorCode: InvalidRequest)

This PR is a copy of #37 but under Honeycomb's repository because of permissions issues

• Closes fix: Use AWS::Partition Pseudo Parameter in IAM ARNs  #37
• Thank you to @dougireton for the details

Short description of the changes

Swap the hardcoded AWS partition with the AWS Partition Pseudo Parameter, AWS::Partition

1. Allow CloudWatch Logs service in non-default AWS Partitions to assume LogStreamRole

2. For RDS Logs TransformLambdaRole, use correct AWSLambdaBasicExecutionRole ARN for non-default AWS Partitions

How to verify that this has the expected result

Deploy RDS Logs or CloudWatch Logs templates in AWS GovCloud.

[JamieDanielson]

Actually can we change the title and details to reflect the changes in the original PR?