Refactor TableView class so things like datasette-graphql can reuse the logic

[simonw]

Originally posted by @simonw in simonw/datasette-graphql#2 (comment)

[simonw]

datasette-graphql uses the logic from TableView right now. It wasn't too unpleasant, but I do worry about the two of them being coupled together in this way.

https://github.com/simonw/datasette-graphql/blob/cc65ec294b0bf8e26213fc68bb5487066de9caab/datasette_graphql/utils.py#L412-L417

        request = Request.fake(path_with_query_string)

        view = TableView(DatasetteSpecialConfig(datasette))
        data, _, _ = await view.data(
            request, database=database_name, hash=None, table=table_name, _next=after
        )

[simonw]

I'm actually pretty happy with how datasette-graphql works now - maybe the trick here is to redesign the JSON format in #782 such that it can be used as a documented interface by things like datasette-graphql and then ensure Datasette has a documented mechanism for dispatching internal requests.

I just did a horrible hack here that simulates an internal request, so supporting them as a feature would definitely make sense: natbat/rockybeaches@ec102c6

[simonw]

I'm closing this in favour of an internal requests mechanism in #943.