Tox and Zuul job for the bandit code scan in stx/stx-puppet

Setting up the bandit tool for the scanning of HIGH severity issues
in the python codes under Starlingx/stx-puppet folder.
Expecting this merge will enable zuul job for CI/CD of bandit scan.

Configuration files:
1. tox.ini for adding bandit environment and command.
2. test-requirements.txt for adding bandit version.
3. .zuul.yaml file for adding bandit job and configuring under
   check job to run code scan every time before code commit.

Test:
Run tox -e bandit command inside the fault folder to validate the
bandit scan and result.

Story: 2007541
Task: 39687
Depends-On: https://review.opendev.org/#/c/721294/

Change-Id: I2982268db2b5e75feeb287bc95420fedc9b0d816
Signed-off-by: Sharath Kumar K <sharath.kumar@intel.com>

.zuul.yaml

@@ -1,5 +1,7 @@
 ---
 - project:
+    templates:
+      - stx-bandit-jobs
     check:
       jobs:
         - stx-puppet-linters

test-requirements.txt

@@ -1,3 +1,4 @@
 # hacking pulls in flake8
 hacking!=0.13.0,<0.14,>=0.12.0 # Apache-2.0
 bashate >= 0.2
+bandit!=1.6.0,>=1.1.0,<2.0.0

tox.ini

@@ -81,3 +81,8 @@ show-source = True
 ignore = E123,E125,E501,H405,W504
 exclude = .venv,.git,.tox,dist,doc,*lib/python*,*egg,build,release-tag-*
 
+[testenv:bandit]
+basepython = python3
+description = Bandit code scan for *.py files under config folder
+deps = -r{toxinidir}/test-requirements.txt
+commands = bandit -r {toxinidir}/ -x '**/.tox/**,**/.eggs/**' -lll