AOI Analysis Area creation should be clearer.

[wmbeers]

Users have expressed some confusion about the Analysis Areas screen, it's purpose, and utility. In addition to issues related to how this tool dynamically creates the analysis area polygons based on user input (see #71).

To address this I created a mockup, committed to branch https://github.com/wmbeers/cmv-app/tree/AOI-Enhancement-Mockup, captured in the attached
Presentation

Presented to users on 1/20, but this proposed change didn't really help clarify things. It wasn't just the wording, but the workflow as well. Discussed in a deeper dive meeting on 1/27, we settled on just giving the users the option to union the buffers of all features to a single analysis area, or create individual analysis areas for each feature. The more complex third option shown in the presentation isn't a use case they think they need, and can be accomplished by just creating another AOI.