Add staging and production CICD

[eoinsha]

As a SLIC Lists developer, I want changes committed to master to be deployed to staging and production automatically so that I don't have to spend time manually deploying and I get quick feedback on the outcome of new features.

Acceptance Criteria

1. The process should run unit tests
2. The process should run integration and E2E tests
3. Every service should be deployed if its code has changed
4. No manual configuration or intervention should be required except for production approval

[eoinsha]

TODO:

• Include cross-region deployment of certificates to us-east-1
• Replicate staging phase to prod
• Add manual approval stage