Fix compose

    - For mongo service, change the "sleep 3" instruction into "mongostat -n 1".
    The instruction meant to wait for the server startup procedure.
    Mongostat should print up when such procedure are completed meanwhile "sleep"
    is infrastucture dependent
    - For opensilex service, reply the "chown" command at the entry point time.
    The mounted volume remaind owned by root:root otherwise and the config file
    could not be generated.