plugin Pubsub Hook: first draft: This new plugin allow to attach an external action to a Pubsub event (i.e. notification). Hook can be persitent accross restarts, or temporary (will be deleted on profile disconnection). Only Python files are handled for now. In the future, it may make sense to move hooks in a generic plugin which could be used by ad-hoc commands, messages, pubsub, etc.

Use this module to temporary store files that need to be integrated to other
projects such as Wokkel.

For example, the changeset that introduced this folder adds RSM (XEP-0059)
support to Wokkel. The files in sat.tmp.wokkel are imported over the initial
wokkel files from sat.plugins.__init__.py