fix(keycloak): Fix infinispan magic

This patch adds the infinispan cache configuration for keycloak to allow
proper HA deployment with all caching goodies.

Turns out it's important to add the ping port (7800) to the headless
service in order to run the inifispan setup for kubernetes.

This was pieced together by some nice community posts, see:
https://gist.github.com/pedroigor/e1476a41b544d15c1bd59155aad4f6ad
https://github.com/keycloak/keycloak/issues/9644#issuecomment-1016850466
https://github.com/keycloak/keycloak/discussions/10125

Further the strategy Recreate was removed since it's not needed and the
inifispan will allow to always keep one keycloak instance around.