Use an existing db cluster parameter group instead of creating new one

[topikachu]

Describe the Feature

Since the cluster parameter group is not adjustable, it's not feasible that always create a new cluster parameter group in a large system.

Expected Behavior

Add a new db cluster parameter group name.
Use an existing db cluster parameter group if specifying.

Use Case

We have a large developing team that creates a lot of rds serverless clusters for development and testing.
Since the db cluster parameter group number is not adjustable, we can't create more.

Because nearly all of these RDS clusters are for testing only, a shared default cluster parameter group is acceptable in our environment.

Describe Ideal Solution

Add a new db cluster parameter group name.
Use an existing db cluster parameter group if specifying.

Alternatives Considered

Change to db instance as a workaround, however, it's not cost-efficient. A serverless cluster is very good for us for RnD testing.

Additional Context

No response