docs: Simplify microk8s instructions
docs: Simplify microk8s instructions

These days, microk8s has the plugin that makes it really easy to get up
and running. Rely upon that plugin instead of having these complicated
instructions.

Signed-off-by: Joe Stringer <16a9a54ddf4259952e3c118c763138e83693d7fd@cilium.io>

cilium/cilium,michi-covalent/cilium,tklauser/cilium,michi-covalent/cilium,cilium/cilium,tklauser/cilium,tgraf/cilium,cilium-team/cilium,tklauser/cilium,tgraf/cilium,tklauser/cilium,cilium/cilium,tgraf/cilium,cilium-team/cilium,michi-covalent/cilium,tklauser/cilium,tgraf/cilium,tgraf/cilium,michi-covalent/cilium,cilium/cilium,cilium/cilium,tgraf/cilium,michi-covalent/cilium