A job which simply runs project's own ci/build.sh

One cannot apparently inherit playbooks from a parent job, so let's copy
that Ansible file from the zuul-jobs repo and be done with it.

Change-Id: Iabb64d36f23f451b9b46372e54c0d19d82587a04
diff --git a/playbooks/run-test-command/run.yaml b/playbooks/run-test-command/run.yaml
new file mode 100644
index 0000000..aa87128
--- /dev/null
+++ b/playbooks/run-test-command/run.yaml
@@ -0,0 +1,7 @@
+- hosts: all
+
+  tasks:
+    - name: Run test_command
+      command: '{{ test_command }}'
+      args:
+        chdir: '{{ zuul.project.src_dir }}'