This commit changes the way kuryr-cni is executed in containerized
deployments. Now it'll use `docker exec` command to execute kuryr-cni
inside the CNI container. This should make it easier to be consumed by
deployers.
To be able to do such changes I needed to stop mounting host's /etc
directory. I believe this was unnecessary and was blocking curl from
working in isolation from host OS.
Closes-Bug: 1757531
Change-Id: I373d65536a43eab98f0fc708936b97637f82eaff
206c158d37