Modify hacking flake8 extension

Move hacking files to dir used by the rest of the projects
Use the hacking factory option to allow for additional checks

Change-Id: If498bb4a2d1ce85c51abd04a559e9106febf4027
diff --git a/tox.ini b/tox.ini
index d6c2c41..924e844 100644
--- a/tox.ini
+++ b/tox.ini
@@ -60,7 +60,7 @@
        -r{toxinidir}/tools/test-requires
 
 [hacking]
-local-check = tools.hacking.tempest.skip_bugs
+local-check-factory = tempest.hacking.checks.factory
 
 [flake8]
 ignore = E125,H302,H404