Replace ntpd with chronyd in installation
    
    Completely remove ipaserver/install/ntpinstance.py
    
    This is no longer needed as chrony client configuration
    is now handled in ipa-client-install.
    
    Part of ipclient/install/client.py related to ntp configuration
    has been refactored a bit to not lookup for srv records
    and/or run chrony if not necessary.
    
    Addresses: https://pagure.io/freeipa/issue/7024
    Reviewed-By: Rob Crittenden <rcritten@redhat.com>