Feature/add more ubuntu distributions

[aaroncwhite]

• Refactored into a simpler format for building any base ubuntu image.
• Added eoan to list of images to build.

Cool project! Hope it stays active.

[pauldotknopf]

I've been meaning to do this, but as well, but when I need to change it, I always say "fuck it."

Thanks!

PS: I think the Debian build could be wrapped up into it as well, but I don't think anyone is using it.