Create container image with all necessary tools and latest groff and mom

[sschober]

As I reported some bugs, which were fixed but are not yet released and to ease the overall burden to try mato, I think it would be great to have a single container image containing:

• groff 1.23
• mom git latest
• pdfinfo (from xpdf might be hard)
• Imagemagick

[sschober]

This is espacially interessting, as there is a fix for gropdf from Deri James, which reduces the size of produced PDFs by several factors, as it uses partial font embedding.