[VOL-2282]

Run robot tests with Python 3

- Remove HTTP and database robot libraries that aren't used
- Make robot lint treat warnings as errors
- Reformat robot tests to pass lint, and other minor fixes
- Lint/reformat of python code
- Add yaml and json linting
- Clean up Makefile
- Assume the KUBECONFIG and VOLTCONFIG env vars are defined

Change-Id: Ibf0a6b525802ed907efc38b34c8e3b99b2044bf1
diff --git a/variables/variables.robot b/variables/variables.robot
index 4415d23..1fb3327 100644
--- a/variables/variables.robot
+++ b/variables/variables.robot
@@ -18,6 +18,6 @@
 ${ONOS_REST_PORT}    30120
 ${ONOS_SSH_PORT}    30115
 ${OLT_PORT}       9191
-@{PODLIST1}   voltha-kafka  voltha-ofagent
-@{PODLIST2}   bbsim  etcd-operator-etcd-operator-etcd-operator   radius  voltha-api-server   voltha-cli-server   voltha-ro-core    voltha-rw-core-11
-
+@{PODLIST1}       voltha-kafka    voltha-ofagent
+@{PODLIST2}       bbsim    etcd-operator-etcd-operator-etcd-operator    radius    voltha-api-server
+...               voltha-cli-server    voltha-ro-core    voltha-rw-core-11