Add initial layout files

[Locke]

• [x] TUDa Pub
• [ ] TUDa Thesis
• [ ] TUDa Beamer
• [ ] TUDa Exercise
• [ ] TUDa Report
• [ ] TUDa Announcement
• [ ] TUDa Letter
• [ ] TUDa Poster
• [ ] TUDa SciPoster
• [ ] TUDa Leaflet

(order based on my assumption of importance and required effort)

[Locke]

I started to work on TUDa Beamer and TUDa Exercise. A dirty / intermediate version can be found in the dev branch.

TUDa Report, TUDa Announcement and TUDa Letter might be good first PRs if anyone is interested.