[services][terraform] Import VPC

Summary:
Imported our VPC configuration to Terraform.
Imported it as-is, didn't change anything in AWS.

Depends on D8571

Test Plan: Terraform plan results in no differences between current state and remote.

Reviewers: jon, varun, michal

Reviewed By: jon, varun

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D8582