[enhancement] Some tunnel types not currently in the cheatsheet

[apwiggins]

Saw this list by Hangbin Liu recently which has some tunnel types not in the cheatsheet
https://developers.redhat.com/blog/2019/05/17/an-introduction-to-linux-virtual-interfaces-tunnels/
IPIP Tunnel
SIT Tunnel
ip6tnl Tunnel
VTI and VTI6
GRE and GRETAP
IP6GRE and IP6GRETAP
FOU
GUE
GENEVE
ERSPAN and IP6ERSPAN

[Strider3000]

GENEVE would be especially helpful.