[Clipart] svgz support

[Wolfgang Spraul]

> it seams that they are not in database at all. This return 0:
> select count(*) from ocal_files where filename like '%.svgz'

yes but why? :-)
Any insight into the history of this? I will do a quick matchup
between files & database entries these days, maybe there are more
files without any db entries?

If nobody knows the history, I will just try to do 'the right thing'
assuming that this is all good & valid stuff and I will recreate
database entries and make them reappear. In the case of svgz, I will
unzip them and drop support for uploading .svgz (if that even works
now, unlikely since no new .svgz have been uploaded in 3 years).

That way we can focus on svg... Anybody with historical knowledge?