Make it obvious to a repo visitor what Exosphere does

(formerly "Animated GIF/movie to showcase functionality")

Possible ways to solve:

• Animated GIF/movie to showcase functionality
• A few bullet points in the readme mentioning what our features/goals are
• An ideals/goals/motivation section a la https://cockpit-project.org/ideals.html
• A demo cloud that people can point to (this might be sort of dangerous), OR app "demo mode"?? This is probably a rabbit hole, don't step in it

I think this issue would be solved/closed once a moderately computationally literate person (or a domain scientist) can visit our repo and, in 2 minutes or less, get an idea of what we're doing and whether or not it's something useful for them.