Add tempest post-run cleanup script

Implemented all features defined in blueprint.

Change-Id: If3c9b82f85095eeb22bbf32841be534024213567
Implements: blueprint post-run-cleanup
diff --git a/setup.cfg b/setup.cfg
index 5c62710..2e25ace 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -22,6 +22,7 @@
     verify-tempest-config = tempest.cmd.verify_tempest_config:main
     javelin2 = tempest.cmd.javelin:main
     run-tempest-stress = tempest.cmd.run_stress:main
+    tempest-cleanup = tempest.cmd.cleanup:main
 
 [build_sphinx]
 all_files = 1