Payara Docker image improvement with Payara Server 172

[OndroMih]

The ENTRYPOINT in payara/Dockerfile can be improved with the new --postbootcommandfile argument of the start-domain command, so that the Payara Server can be executed in the foreground as the main Docker process.

ENTRYPOINT echo deploy ${DEPLOYMENT_DIR}/${WAR} > deploy-command && \
           asadmin start-domain --verbose --postbootcommandfile deploy-command ${DOMAIN_NAME}

A more complex command to support deployment of all apps in a directory is used in the official Payara Docker Dockerfile and images hosted in the Docker hub