Drop extreme sysctl tuning
    
    No longer use legacy, unmaintained, and questionable tuning options.
    
    Noteable:
     - we no longer use iptables, but nftables
     - we _do_ want IPv6 autoconfiguration
     - we do _not_ want to tamper with swapping or nework logic unless
       explicitly documented why
     - non-local binding should _only_ be allowed on machines requiring it
    
    Signed-off-by: Georg Pfuetzenreuter <georg.pfuetzenreuter@suse.com>