Draft: Include all files in tree

Accounts for all changed files in changes tab

When file (or other diff limits) are exceeded, not all files are displayed in the MR changes tab. This is reasonable for performance considerations. However users may want to at least have all their changes represented there for accounting/UX reasons, regardless of whether there is an accessible patch to access. This PR allows files that exceed hard limits to be present in the change tab file tree, but does not even attempt to persist any more information for the patch beyond the path.

I'm aware this is a fairly heavily debated concept, I am welcome to any/all suggestions. This is a rough implementation dependent on a companion MR in gitaly and is subject to heavy changes.