AWS::RDS::DBInstance Database Activity Streams Feature Request

### Name of the resource

AWS::RDS::DBInstance

### Resource name

_No response_

### Description

Amazon RDS DB instance supports [database activity stream](https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/DBActivityStreams.Enabling.html) to audit database activity.

This is possible via Console or CLI/API as we can see in the referenced doc. However, it is not available in the CloudFormation Resource Type [AWS::RDS::DBInstance](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-rds-dbinstance.html) .

This is a request to add the feature in CloudFormation for the Resource Type `AWS::RDS::DBInstance`.

Related GH issue(FR) #1596 for AWS::RDS::DBCluster

### Other Details

_No response_

Start with the linked AWS documentation for enabling database activity streams and inspect related issue #1596 for AWS::RDS::DBCluster. Done means AWS::RDS::DBInstance exposes equivalent database activity stream support through CloudFormation.

Written by the indexing model from the issue text.