Allow multiple dynamic index files

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In some cases you want to serve /index.html and /otherApp/index.html as two separate applications. We currently only support a routable application at the root of the site. This means that we need to load all assets of the whole site even if it's likely a user won't be accessing all parts of the site that use them.

It would be nice if we would walk back from the currently location to the root looking for index.html.js files. As soon as we find one we use it for routing.

The most use case I was first thinking of was having an admin area at /admin. Admins however have a login and thus don't need server-side rendering. So this would not be a valid use case.

I think we only need to solve this once we have a solid use case.

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No use case has presented itself. I think that, once we have a use case, we might want to investigate switching to something like next-js.

Closing this issue for now.

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One of the use cases is the Sanity studio in a sub directory.