Get and set DCOS CLI configuration properties

Usage:
    dcos config --info
    dcos config append <name> <value>
    dcos config prepend <name> <value>
    dcos config set <name> <value>
    dcos config show [<name>]
    dcos config unset [--index=<index>] <name>
    dcos config validate

Options:
    -h, --help       Show this screen
    --info           Show a short description of this subcommand
    --version        Show version
    --index=<index>  Index into the list. The first element in the list has an
                     index of zero

Positional Arguments:
    <name>           The name of the property
    <value>          The value of the property
