apps.intel_avf: add VLAN filter/stripping/insertion support
apps.intel_avf: add VLAN filter/stripping/insertion support

Also: set a required reserved bit in txdesc (not sure if it had an effect)
(cherry picked from commit e3dd48ff4a3a5a272fba4ffad611c153a486e195)

snabbco/snabb,Igalia/snabb,snabbco/snabb,snabbco/snabb,Igalia/snabb,Igalia/snabb,snabbco/snabb,Igalia/snabb,eugeneia/snabb,Igalia/snabb,eugeneia/snabb,SnabbCo/snabbswitch,eugeneia/snabb,snabbco/snabb,eugeneia/snabb,snabbco/snabb,eugeneia/snabb,eugeneia/snabb,SnabbCo/snabbswitch,snabbco/snabb,Igalia/snabb,Igalia/snabb,eugeneia/snabb,SnabbCo/snabbswitch,eugeneia/snabb,Igalia/snabb,snabbco/snabb,SnabbCo/snabbswitch