Set up web handler for hosted content

[i-hardy]

What does this change?

This sets up a basic initial web rendering path for hosted content in DCR, using the scaffolded layouts.

Why?

This is part of an ongoing piece of work to migrate hosted content to DCR. Setting this up enables us to test hosted content rendering locally using the usual dev setup as we build on the initial scaffolds.

This will need revisiting when we get closer to launch as it's currently not possible to provide the data required to populate window.guardian or set up a lot of basic page config, but this will require changes in frontend and may be subject to the actual requirements of the pages themselves.

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[gu-prout[bot]]

Seen on PROD (merged by @i-hardy 13 minutes ago) Please check your changes!