Use Horizon project template for django jobs

Horizon defined a project template 'horizon-non-primary-django-jobs'
for django jobs. This patch use that template to run django jobs
here. For information please refer [1]

[1] https://review.opendev.org/#/c/681969/

Change-Id: I0d1349fc71ab3779a009b7a612e8f673c8217db9

.zuul.yaml

@@ -1,6 +1,7 @@
 - project:
     templates:
       - check-requirements
+      - horizon-non-primary-django-jobs
       - openstack-python-jobs-horizon
       - openstack-python3-train-jobs
       - release-notes-jobs-python3

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 minversion = 1.6
-envlist = py27,py37,pep8
+envlist = py27,py37,py3-{dj111,dj22},pep8
 skipsdist = True
 
 [testenv]
@@ -11,7 +11,10 @@ setenv =
 deps = -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
        -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
-commands = /bin/bash run_tests.sh -N --no-pep8 {posargs}
+commands =
+  dj111: pip install django>=1.11,<2
+  dj22: pip install django>=2.2,<2.3
+  /bin/bash run_tests.sh -N --no-pep8 {posargs}
 
 [testenv:py27]
 setenv = DJANGO_SETTINGS_MODULE=trove_dashboard.test.settings