[misc] File store is the default since 10.3

10/mysql-tomcat/xwiki/docker-entrypoint.sh

10/postgres-tomcat/xwiki/docker-entrypoint.sh

9/mysql-tomcat/xwiki/docker-entrypoint.sh

9/postgres-tomcat/xwiki/docker-entrypoint.sh

template/xwiki/docker-entrypoint.sh