Refactor Frontend Implementation to agree with implementation of IAMFrontend

The Frontend-Implementation document was written before the plan to include an IAMFrontend existed. This document will need to be refactored (totally rewritten) to reflect how and where JWTs from Keycloak will be stored and passed around the application.

Once this is known, this will allow for other repositories to use that as the metric for redirect to IAMFrontend. For example, if a token would be stored as a cookie, then the absence of that cookie dictates that a redirect to IAMFrontend is needed.

Additionally, the section in the README file should be made more specific to explain the implementation.