Create CNNS versioning scheme and improve dependency management

[adodon2go]

• Currently we build vl3 & vl3_kiknos images and publish them to Docker Hub:
  • if CIRCLE_USERNAME is tiswanso it will publish under tiswanso user (@tiswanso you will need to add cnns-publish with DOCKER_USER and DOCKER_PASS for your Docker Hub account under your CircleCI project)
  • otherwise it will publish under cnns user
• In case you do a git tag (on official or on your forked repo), vl3 & vl3_kiknos images will be published with the git tag (Ex: cnns/ucnf-kiknos-vppagent:vl3-v0.1.2 or cnns/vl3_ucnf-vl3-nse:vl3-v0.1.2)
• if CIRCLE_USERNAME is tiswanso images will be published with tag ${CIRCLE_BRANCH} (Ex: vl_latest, vl3_stable,etc)
• if CIRCLE_USERNAME is not tiswanso, images will be published with ${CIRCLE_SHA1} tag
• Updated CircleCI config to pass tests

[tiswanso]

IMO, we don't want to remove the e2e job. It's actually failing for a few reasons but the primary one is that the config lib is returning failures and the nse control binary is exiting.

If I run the nse-binary manually (via in an ssh circleci session):

root@vl3-nse-ucnf-747b5588d4-m9t2r:~# /bin/cnf-vppagent
INFO[0000] Waiting for liveness probe: tcp:localhost:9113
INFO[0000] Resetting vppagent...
INFO[0000] Finished resetting vppagent...
ERRO[0000] error: yaml: unmarshal errors:
  line 5: field cnns not found in type config.Endpoint
  line 9: field vl3 not found in type config.Endpoint
FATA[0000] Error processing [/etc/universal-cnf/config.yaml]: yaml: unmarshal errors:
  line 5: field cnns not found in type config.Endpoint
  line 9: field vl3 not found in type config.Endpoint

I can morph this PR into what I'm thinking for labels as well.