Limit e2e test environment age to improve test stability

[hessjcg]

Ensure that the CI environments for e2e tests are only valid for 1 week. Then they are deleted and recreated fresh. This will help ensure that the environments remain stable.

• Update naming of clusters, dbs, vpcs etc to include the validity date, so that there are no naming conflicts.
• Create a cleanup job that will delete old environments without using terraform. (Terraform is slow and unreliable for env teardown.)