[packagekit] splitting python into frontend and backend

[Richard Hughes]

At the moment lib/python contains a mix of files used by the backends,
and files used by front-end clients.

I propose making:

lib/python/*.py               for all the client side stuff
backends/helpers/python/*.py  for all the backend stuff

The former would install to the
existing /usr/lib/python2.5/site-packages/packagekit, and the second
to /usr/lib/python2.5/site-packages/packagekit-backend

This also allows us to create backends/helpers/perl for the urpmi
backend.

What do you think?

Richard.