interfaces: convert the repository zope interfaces to Protocol classes This is the same transformation as 382d9629cede did for dirstate. The same caveat applies- the code may not be valid, since the functions are missing the `self` arg, and the attrs should be plain attrs, not zope `Attribute`. These classes are pretty intertwined however, so making the same transformation to everything makes it easier to change and review. Additionally, there are some classes that subclass multiple protocol classes, and should themselves subclass `typing.Protocol` to be a protocol class. But defer that for now for clarity.