Filters the unit type. (FIELD_ROOT_UNKNOWN=0 / CONSUMER_UNIT=1 / PICTURE=2 / VIDEO=3 / ENRICHED_CONTENT=4 / DOCUMENT=5 / SHARING_UNIT=6 / DISPLAY_UNIT=7 / LOGISTICAL_UNIT=8 / RFP_EVENT=9 / RFP_BU=10 / RFP_SUPPLIER=11 / ORGANIZATION=12 / RFP_PROPOSAL=13)