Add DB Snapshots ID's as an AWS Specific Parameter

### Name of the resource

Other

### Resource name

Parameters

### Description

Within CloudFormation templates that need to dynamically list a set of specific objects within a Drop down list, the AWS-Specific Parameters seen within this document [1] allows for items such as EC2 Security Groups that exist within the account to present themselves in a Drop Down list.

The only other way to present a Drop Down list with functionality akin to an AWS Specific Parameter would be to manually place each available value within the AllowedList property of the "String" type Parameter.

Requesting that DB Snapshot ID's be added in as a supported AWS Specific Parameter so that a dropdown menu of available and existing DB Snapshots present themselves as the workaround to achieve this functionality is limited to updating the template prior to Stack Creation.

The only workaround at the moment for having a DB Snapshot ID parameter list to become dynamic is to use a Lambda Function to parse for all available DB Snapshots at a given time interval, and then place these DB Snapshot ID's into the "AllowedList" section of the Parameter and place the edited template back into S3 for use.

--------------------References--------------------

[1] AWS-specific parameter types

https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/parameters-section-structure.html#aws-specific-parameter-types

### Other Details

_No response_

Start with the linked AWS-specific parameter types reference and the CloudFormation template Parameters section. Define how DB Snapshot IDs should appear as a dynamic selection and verify that existing snapshots are supported without updating the template before stack creation. The issue names no repository files or tests, so the implementation entry point still needs to be found.

Written by the indexing model from the issue text.