Removes the it `fails to execute confListDel given no 'plugins' key"` test.
This test no longer fails after libcni version 1.2.3.
It probably shouldn't failduring a DEL action as it is, we want the least error prone path.
The GC test now uses both cni.dev attachment formats.
Uses both attachment formats as per https://github.com/containernetworking/cni/issues/1101 for GC's cni.dev/valid-attachments & cni.dev/attachments
This commit changes thin container base image to distroless
to simplify container image. It replace old shell script entrypoint
to golang implementation and implement multus installer (i.e. copy).