Add storage_throughput for better gp3 support

[asiegman]

what

• Add storage_throughput option, as described in the provider

why

• Need this for gp3 storage types if not using the default for your given allocated_storage

references

• https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/db_instance#storage_throughput

[asiegman]

Of note, I tried to run make lint and make readme locally, but both were very broken for me. Decided to throw up the PR and hope you autofix via workflows and terraform-docs like we do in our terraform repos =)

Edit: Looks like Auto-Format hit a lot of stuff I haven't touched. Weird.

[nitrocode]

/test all