Setup cloudfront to point to front ends (dev, test, prod)

This ticket is to set up cloudfront to point our backend to the correct front ends.

**Acceptance Criteria:**
- dev front end exists for register admin
- test front end exists for register admin
- prod front end exists for register admin (vanity url to be set up later)
- Team has access to all 3 urls - please paste links here: https://apps.nrs.gov.bc.ca/int/confluence/display/BCPRS/Park+Names

**Notes**
- relates to #35
- decision in #35 around dev/test and prod env will affect how these front ends are set up

Start by reading issue #35, since its decision about dev, test, and prod environments affects this setup. Review the Park Names Confluence page linked in the acceptance criteria for the required environment URLs. Done means all three register-admin front ends exist, CloudFront routes the backend to the correct front end for each environment, and the team can access all three URLs.

Written by the indexing model from the issue text.