New Resource: SSLCertificate & RegionSSLCertificate

[Duologic]

What resource do you need?

I'm interested in using the resources SSLCertificate.compute and RegionSSLCertificate.compute. I see that this one is available in the -preview version, @muvaf suggested on Slack to create an issue here to add them to the 'regular' version.

What is your use case?

We get these certificates from cert-manager and like to inject them into GCP.

Would you be willing to contribute it using Terrajet?

I wouldn't mind creating a PR if necessary, from the Slack thread I got a sense this would be easy to do by the maintainers.