Lockdown API URL to `api.<efcms_domain>`

Pre-Conditions

During a deployment, a step should open up the deploying-color api endpoint api-<deploying_color>.<efcms_domain> to test the deploying color before we switch-colors
The switch-colors step move api-<deploying_color>.<efcms_domain> to api.<efcms_domain>, and disable <deploying-color>.<efcms_domain>.
The currently deployed UI at app.<efcms_domain> talks only to api.<efcms_domain>.
This makes api-<current_color>.<efcms_domain> obsolete, and it should not respond to requests.
This also makes app-<current_color>.<efcms_domain> obsolete, and it should forward to app.<efcms_domain>
In other words, app-<deploying_color>.<efcms_domain> and api-<deploying_color>.<efcms_domain> are only live between the step to open it up for testing and the switch-colors step.
The API should reject a request from a user who is on an older version of the UI who is still on a page that has a previously deployed version of the app should be warned that their browser is out of date. (could be broken out into its own story)

N/A

[ ] Does this work make you nervous about privacy or security?
[ ] Does this work make major changes to the system?
[ ] Does this work implement new authentication or security controls?
[ ] Does this work create new methods of authentication, modify existing security controls, or explicitly implement any security or privacy features?

Could create another issue to handle the final AC item.

Product Owner

Engineering

[ ] Automated test scripts have been written
[ ] Field level and page level validation errors (front-end and server-side) integrated and functioning
[ ] Paired w/Mark on data migration work (if applicable)
[ ] Verify that language for docket record for internal users and external users is identical
[ ] New screens have been added to pa11y scripts
[ ] All new functionality verified to work with keyboard and macOS voiceover https://www.apple.com/voiceover/info/guide/_1124.html
[ ] READMEs, other appropriate docs, JSDocs and swagger/APIs fully updated
[ ] UI should be touch optimized and responsive for external only (functions on supported mobile devices and optimized for screen sizes as required)
[ ] Module dependencies are up-to-date and are at the latest resolvable version (npm update)
[ ] Errors in Sonarcloud are fixed https://sonarcloud.io/organizations/flexion-github/projects
[ ] Lambdas include CloudWatch logging of users, inputs and outputs
[ ] Interactors should validate entities before calling persistence methods
[ ] Code refactored for clarity and to remove any known technical debt
[ ] Rebuild entity documentation
[ ] Acceptance criteria for the story has been met
[ ] Deployed to the dev environment
[ ] Deployed to the stage environment