Ticket 49258 - Allow nsslapd-cache-autosize to be modified while the server is running
    
    Bug Description:  Previously you're not allowed to set nsslapd-cache-autosize, and
                      nsslapd-cache-autosize-set while the server was running.  The only
                      way to set it was to edit the dse.ldif
    
    Fix Description:  Allow it to be set while the server is running.  Also added value
                      validation for these settigs
    
    https://pagure.io/389-ds-base/issue/49258
    
    Reviewed by: tbordaz(Thanks!)