The authcodegrant samples were initially meant to be very simple
demonstration of authorization code flow. However, it has become
obvious since then that the real intent of the demo is how to use
the WebClient with OAuth (there is no other reason to do authorization
code flow unless you use the token to make a request).
The samples have been migrated to oauth2webclient and oauth2webclient-webflux
respectively. They have been improved:
* The sample demonstrates usage with annotations, webclient directly, form login
oauth2Login, and public APIs
* The samples externalize the endpoint that is requested in the sample
making it easier to try other endpoints
* The UI no longer relies on a data structure for the result of the
endpoint also making it easier to try other endpoints
Issue: gh-4921
