Ticket 48864 - Add cgroup memory limit detection to 389-ds
    
    Bug Description:  Previously our memory limits only check hardware
    limits and shell resource limits. However, we may be in a container
    like docker or lxc, and unable to detect these limits. This can lead
    to crash conditions or worse, especially with autosizing
    on import we may have conditions where the server may not
    even be able to install.
    
    Fix Description:  Add support for cgroup memory limit detection
    so that we can properly determine our resource availability regardless
    of lxc, docker, systemd or others.
    
    https://pagure.io/389-ds-base/issue/48864
    
    Author: wibrown
    
    Review by: mreynolds (Thanks!)