[Cabal] themes and plugins

[Luke Schierer]

In one version of the webpage, we had a custom database set up by
chipx86 for handling themes.  That broke, so we replaced it with a
tracker in the SF project page to mirror the long-existing one for
plugins.

As we migrate to trac, I do not want either of these trackers to be part
of the bug/rfe/support stuff.

1)they aren't really tracker items in the same sense.  They do not get
closed.  They are not really up for inclusion, even though it *looks*
like they are.

2)it opens up the system to look like it is for support for plugins or
requests for plugins

3)They should be accessible to more than just developers, and so putting
them in developers.pidgin.im doesn't seem appropriate.

4)They will cause clutter and noise in the interface for dealing with
real tickets.

If then we choose not to put them in trac, we need some other interface
for them.

luke