[Terraform] sql private ip support

[danawillow]

Based off of hashicorp/terraform-provider-google-beta#145

---

[all]

[terraform]

Website changes for SQL private IP + new computed field

[terraform-beta]

Close this PR in favor of #145.

[ansible]

[inspec]

[googlebot]

We found a Contributor License Agreement for you (the sender of this pull request), but were unable to find agreements for all the commit author(s) or Co-authors. If you authored these, maybe you used a different email address in the git commits than was used to sign the CLA (login here to double check)? If these were authored by someone else, then they will need to sign a CLA as well, and confirm that they're okay with these being contributed to Google.
In order to pass this check, please resolve this problem and have the pull request author add another comment and the bot will run again. If the bot doesn't comment, it means it doesn't think anything has changed.

[danawillow]

This code is in a third party directory not subject to Google's CLA rules.

[modular-magician]

I am a robot that works on MagicModules PRs!

I built this PR into one or more PRs on other repositories, and when those are closed, this PR will also be merged and closed.
depends: hashicorp/terraform-provider-google-beta#150
depends: hashicorp/terraform-provider-google#2509

[craigdbarber]

Thanks for taking care of this.