rust-dirstate: introduce intermediate struct for dirstate-v2 data This is passed often as a long tuple that is not easy to know the form of, so we refactor everything in this struct. This also renames `wdir_tracked` to follow the Python `wc_tracked`, even though the on-disk format uses `WDIR_TRACKED`. I think a single naming scheme is better, but we can't easily break the Python impl now because of extensions, so this is low-effort enough and facilitates grepping. Differential Revision: https://phab.mercurial-scm.org/D12498

dirstatemap: remove unused parameter from `reset_state` This has no callers using it and is not used inside the method itself. Differential Revision: https://phab.mercurial-scm.org/D12497

dirstatemap: move `set_tracked` out of common methods and plug in Rust We now have a Rust-specific implementation of this method, it is no longer shared between both implementations. Differential Revision: https://phab.mercurial-scm.org/D12496

rust-dirstatemap: add `set_tracked` method This is the new dirstate API that has already been moved to in Python. It will be used in place of the old `addfile`/`removefile` one. Differential Revision: https://phab.mercurial-scm.org/D12495