Move `routes/index.ts` to `routes.ts`

[slifty]

We define entity routes in our controllers which means that routes/index.ts being an index in a directory is not quite necessary / conveys an intention to have routes all defined in that directory.

FWIW I think routes in a routes directory is a reasonable approach but also think that stela's approach is legitimate (and better in some ways since it allows the dev to define auth middleware in line with route handler implementation)!

I just suggest we tweak this aspect of the implementation to be more clear of intent in directory structure.