fix: update docker compose to match identity url changes

[Ben-Sheppard]

Description

I've seen a couple of instances both internal and external where the docker-compose in this repo isn't fully supportive of recent component changes relating to the Keycloak URLs used for token refresh and revoke.

This PR tries to bring them inline (testing locally shows success), but there are a couple of things to note:

• Identity uses the "frontend" or the ISSUER_URL of keycloak to perform token refresh and revoke
• To be able to resolve the URLs correctly two things need to happen
  • The KEYCLOAK_HOST variable needs to be set to the container name of Keycloak, in this instance keycloak
  • The local machine should be able to resolve keycloak to 127.0.0.1