Define separate base url between endpoints

Problem/Motivation

I use keycloak as identity provider for my project.
I also use docker with one container for drupal and one for keycloak.

My issue is when the drupal container want to validate the tokens it can't because it try to connect on localhost which is not the correct URL as the generic plugins does.

Steps to reproduce

Create a projet with docker with 3 container (BDD / Druapl / keycloak)

Try to login with keycloak on localhost:8080

Proposed resolution

One solution is to optionally have the choice choice to define the 3 endpoint full url as generic plugin does.

Remaining tasks

User interface changes

API changes

Data model changes