Support Aurora DSQL

[dacevedo12]

Fairly new service https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/dsql.html

[bblommers]

Hi @dacevedo12! @cm-iwata was kind enough to already provide a PR for the create_cluster() operation. Which other operations/features do you want to see supported?

[dacevedo12]

Thanks a lot! I think generate_db_connect_admin_auth_token and generate_db_connect_auth_token will be amongst the most used

[cm-iwata]

In my opinion, implementing generate_db_connect_admin_auth_token and generate_db_connect_auth_token has little effect since these operations don't communicate with DSQL endpoints.
S3 generate_presigned_url performs a similar process, so its not have a moto's implementation.