Add user stories to README

[petebachant]

I am very interested in the high level goals of this project, which appear to be to create a containerized environment for storing and analyzing wind farm data, but I'm not understanding who the target users are and how they interact with the system (get data in, run analyses, build extended functionality on top, etc.). It would be useful to spell out the user personas and stories to make it clear what this system is for.