adding playbook and inventory for jenkins test

playbooks/edx_jenkins_tests.yml

+- name: Configure instance(s)
+  hosts: jenkins_test
+  sudo: True
+  gather_facts: True
+  vars:
+    migrate_db: True
+    mysql5_workaround: True
+    ansible_ssh_private_key_file: /var/lib/jenkins/continuous-integration.pem
+  vars_files:
+    - "{{ secure_dir }}/vars/edxapp_ref_users.yml"
+    - "{{ secure_dir }}/vars/edxapp_sandbox.yml"
+  roles:
+    - common
+    - nginx
+    - edxlocal
+    - edxapp
+    - xqueue
+    - xserver

playbooks/jenkins-inventory.ini

+[jenkins_test]
+jenkins-test.sandbox.edx.org