Document the approach to copy ear/war contents instead of using autoExpand

Document that customers should copy the expanded ear/war at image build time instead of using autoExpand

When <applicationManager autoExpand="true" /> is set in Liberty server configuration and RUN configure.sh is called, the application will be expanded as part of the server start and stop process to generate shared class cache (SCC) to speed up startup time. This will result in the application image containing the app content twice - one as war, the other as expanded directory. This won't be a concern for applications are small in size. But it can significantly increase the image size when the application size is big.

Sample:

FROM icr.io/appcafe/open-liberty:kernel-slim-java11-openj9-ubi
COPY --chown=1001:0 src/main/liberty/config /config
RUN features.sh
COPY --chown=1001:0 target/app-name/ /config/apps/app-name.war/
RUN configure.sh

Start with the Dockerfile example in the issue and locate the existing documentation for Liberty application expansion and autoExpand. Document the image-build approach of copying the expanded EAR/WAR contents instead, including why autoExpand can duplicate application content; done when customers can follow the guidance without relying on autoExpand.