Move `/src/surveys` to `/surveys`

There are two related pieces in this repo - a set of components for rendering surveys, and a library of surveys. It makes sense to group them together into a single repository because they interact so strongly - each is designed to work with the other. However, the components will (eventually) be packaged for npm (https://github.com/Watts-Lab/deliberation-surveys/issues/6) while the survey library will be served from this repository.

It would make sense to separate these concerns, so that everything in the /src folder is packaged for npm, while all the survey .json files and their documenting .mdx files live in /surveys. Unfortunately, this seems to break storybook, because the default webpack settings only look for stories in /src (as far as I can understand from googling it). Moving the directory will require digging through some configuration settings.

This can be done at any point, because we want to force people to refer to stories by the permalink that is associated with the story version, so changes to the directory structure in the repository won't break anything (as they'll be in a new commit).

This will be ready to merge when

[ ] Surveys are moved
[ ] There are no changes visible in chromatic (ie, no missing or added stories)

Watts-Lab / surveys

Move `/src/surveys` to `/surveys` #7

This will be ready to merge when