Remove the Stress framework

It's not used anymore. There was general consensus in Feb 2016
to deprecate it (see [1]) and remove it in Newton.

[1]  [qa] deprecating Tempest stress framework

Change-Id: Ib229985ea2a1fee495c9492c9ce1781e6bac1dc6
diff --git a/releasenotes/notes/remo-stress-tests-81052b211ad95d2e.yaml b/releasenotes/notes/remo-stress-tests-81052b211ad95d2e.yaml
new file mode 100644
index 0000000..aa3a78e
--- /dev/null
+++ b/releasenotes/notes/remo-stress-tests-81052b211ad95d2e.yaml
@@ -0,0 +1,4 @@
+---
+upgrade:
+  - The Stress tests framework and all the stress tests have been removed.
+