terraform-provider-aws3: Import terraform-provider-aws3 as net/terraform-provider-aws3

Replace net/terraform-provider-aws by adding a suffix version so multiple aws
providers can coexists.

Adapt to terraform/provider.mk so that the provider can be used with
Terraform and OpenTofu.
Please note that now it no longer depends on terraform or opentofu so
the desired version should be manually installed.
