[services][terraform] Create remote config

Summary:
Initialized a basic terraform configuration for the remote state. The state will be stored in a S3 bucket in the near future.

Depends on D8567

Test Plan: None yet

Reviewers: jon, varun, michal

Reviewed By: varun

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D8568