Move intltool to External Deps from Dev Platform

[Rodney Dawes <dobey gnome org>]

Hi,

I would like to propose that we remove intltool from the Developer
Platform module set, and place it in External Dependencies. As
intltool is a build tool, rather than a library, and is meant to
be useful outside the scope of GNOME. The project web page and
mailing list are hosted on FreeDesktop, though the mailing list is
basically a spam dump at this point.

As intltool is a generic build tool, it is meant to be used by more
projects than just GNOME, and I would like to start furthering that
ideology. There is currently interest in possibly using intltool for
translatable resources in WINE as well. I think it makes more sense
as an external dep, than as part of the platform modules.

What do you think?

Thanks,
Rodney