Ticket 49331 - change autoscaling defaults
    
    Bug Description:  In autotuning we default to a split of 40% to
    dbcache and 60 to entry. This isn't always the best split, given
    we cap the dbcache.
    
    In some performance tests I noticed an improvement when increasing
    the dbcache so I want to propose we change the scaling to 25% split
    and a cap of 1.5GB.
    
    Fix Description:  Change the values to 25% and 1.5GB cap
    
    https://pagure.io/389-ds-base/issue/49331
    
    Author: wibrown
    
    Review by: mreynolds (Thanks!)