add 'unknown' type to taxonomy expert
add 'unknown' type to taxonomy expert


Former-commit-id: d7ac0146023712b3b88b86a5c6f0f4868a588577
aaronkaplan/intelmq,pkug/intelmq,sch3m4/intelmq,sch3m4/intelmq,aaronkaplan/intelmq,certtools/intelmq,robcza/intelmq,sch3m4/intelmq,pkug/intelmq,robcza/intelmq,certtools/intelmq,sch3m4/intelmq,pkug/intelmq,robcza/intelmq,aaronkaplan/intelmq,pkug/intelmq,certtools/intelmq,robcza/intelmq