core (client): added feedback and sendMessage methods: - feedback method is a helper method to quickly display an info message to user - sendMessage is the method used to send a message in the stream, using message data dictionary. It inclure a trigger point which can't be cancelled, it is intended for e2e encryption method which don't do full stanza encryption. - "send" trigger point is disabled as it is not used at the moment

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