Dont use demandimport anymore
- It shadows not working imports like 491d32a2 without anyone noticing for a long time
- It gives us only grieve with so much modules, so we have to add all of them to the ignore list, which defeats the purpose of demandimport
- Debian removed it from the debian gajim repo already
- Keep a dummy
demandimport.py
until all plugins removed the use of demandimport