CSIT should use (locally built, not remote fetched) containerized CNI (and later Watcher and ODL)

Once COE-30 and COE-22 are completed, what they added should be used in the CSIT.

So the CSIT instead of locally Go building and then directly using the cni and watcher should use the containers.

But it should not use and fetch a (master) container from from a remote container registry (COE-30) but locally build it, so that changes made in a Gerrit are taken into account.

I'm unlikely to have the spare cycles to work on this myself, but can answer Qs anyone who would like to take this on may have on how we could best go about this.