[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/requirements.txt b/requirements.txt
index 924f78b..52e1d59 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,14 +1,10 @@
-cryptography==2.4.2
-docutils
-paramiko==2.4.2
+flake8
 pexpect
-psycopg2==2.7.7
-pygments
+pylint
 pyyaml
 robotframework
-robotframework-databaselibrary
-robotframework-httplibrary
 robotframework-kafkalibrary
 robotframework-lint
 robotframework-requests
 robotframework-sshlibrary
+yamllint