cleanup: terraform modules and prepare them for better integration tests

[yolocs]

Changes:

• Merged all service modules into one modules/jvs-services. And used https://github.com/abcxyz/terraform-modules/tree/main/modules/cloud_run to create services.
• Relocated KMS keyring and service accounts to a module modules/common. These are resources are more "static". Unlike services, these resources usually only need to be created once.
• Revamped ci module to use https://github.com/abcxyz/terraform-modules/tree/main/modules/github_ci_infra and call modules/common to create "static" resources.
  • In the near future, each CI run will deploy new jvs-services to test the new changes with dedicated new services. This allows us to run multiple CIs in parallel.
  • This change will be a breaking change because https://github.com/abcxyz/terraform-modules/tree/main/modules/github_ci_infra will create a different CI service account. After applying the terraform, I need to update the JVS workflow to use the new CI service account.

TODO:

• We will want a terraform module that can bring up the full end-to-end JVS setup: issue