Defaults for container memory limit

[ubrt]

Starting with Keycloak V24, the heap memory is calculated dynamically based on the available memory or memory limit for the container. If no limit is set, this may lead to instability on the workers.

"As the heap size is dynamically calculated based on the total container memory, you should always set the memory limit for the container. Previously, the maximum heap size was set to 512 MB, and in order to approach similar values, you should set the memory limit to at least 750 MB. For smaller production-ready deployments, the recommended memory limit is 2 GB."

See: keycloak/keycloak@34ab2b6

I therefore suggest setting some defaults for the resource limits:

https://github.com/codecentric/helm-charts/blob/master/charts/keycloakx/values.yaml