[ubuntu-art] Responsible persons for proposed themes

[Mikkel Kamstrup Erlandsen]

I suggest we remove the themes on
https://wiki.ubuntu.com/ArtworkTeam/AdditionalThemes without a
responsible person. If there's no responsible person for an idea, I
suggest sticking it somewhere else.

This way it will be clearer where people are actually working.

Also, any themes in the table should prolly have a link like I made for
SandSkater.

Cheers
Mikkel