graphics/synfig*: re-categorize, hand-off MAINTAINER

Chris writes (in the PR mentioned below):

I need to use Synfig. It appears to be in the
wrong category (devel), should be graphics. As it is
an image manipulation application. I also see it's WAY
out of date.

This pr changes devel/synfig to graphics/synfig. As I
also seek to update this port and graphics/synfigstudio;
takes MAINTAINER.

apply the patch, massaging it to maintain INDEX &c. Hands off
maintainership (from ports@).

PR: 257030
Reported by: Chris Hutchinson