Add artifactory cleanup job

This job will periodically clean airship build artifacts from Nordix
artifactory.

Change-Id: I6807b64e4c02f9cdba7d33afce1d9be6fcdbacc6
diff --git a/jjb/airship/projects.yml b/jjb/airship/projects.yml
index 7b67851..48cecb1 100644
--- a/jjb/airship/projects.yml
+++ b/jjb/airship/projects.yml
@@ -42,6 +42,7 @@
     - metal3_ipa_and_ironic_image_building_test
     - airship_integration_test_centos
     - airship_integration_test_ubuntu
+    - artifactory_cleanup
     repo:
       org: "Nordix"
       name: "airship-dev-tools"