Determine if we can reduce database cost with reduced data retention

We are considering the following aspects

• Snapshots : https://gitlab.com/gitlab-com/gl-infra/infrastructure/-/issues/10208
• Backups : https://gitlab.com/gitlab-com/gl-infra/infrastructure/-/issues/10254
• Size of the database itself (groupdatabase team has been exploring this for performance reasons)

Status 2020-07-17

PG Backups storage size has been significantly reduced from https://gitlab.com/gitlab-com/gl-infra/infrastructure/-/issues/10254. Tracking snapshot portion of cost reduction in #10208 to close this out, review of implementation of change in snapshots is under way