Taui: decouple from regional analyses

[trevorgerhardt]

Taui site generation shares a lot of functionality with running a regional analysis, so it was logical to create them in a similar way. In the end, this created the need to check if we are making a Taui site in a variety of places deep throughout the process of running a regional analysis.

We should make Taui site creation a "first class citizen", with a separate end point for creation, a separate database collection, along with a separate handler in the workers to help prevent the need for repeatedly checking whether or not we're creating a Taui site.