rust-dirstate: add `unionmatcher` to the allowed matchers `UnionMatcher` is now implemented in Rust.

rust: add UnionMatcher This will be used in the upcoming support for sparse checkouts in Rust-augmented status and later in rhg support for sparse checkouts.

hg-cpython: refactor matcher transformation logic This reduces duplication and will allow for recursive transformation in UnionMatcher.

rust: use owned types in `Matcher` This simplifies the code a lot, allows for some refactoring to come. The original code tried to prevent allocations that were already happening anyway beforehand.

hg-cpython: fallback when encountering an unknown matcher At this point in the process, nothing user-visible has happened, it is still safe to fallback. This can happen now that we're going to be using "container matchers" like unionmatcher and intersectionmatcher. This is easier and less error-prone than recursive checking beforehand since only the presence of a transformation case will allow the process to continue.

auto-upgrade: add an option to silence the safe-mismatch message For well tested case, the message can get in the way, so we add a way to disable it.

auto-upgrade: add an option to silence the tracked-hint message For well tested case, the message can get in the way, so we add a way to disable it.

auto-upgrade: add an option to silence the dirstate-v2 message For well tested case, the message can get in the way, so we add a way to disable it.

auto-upgrade: rename a variable to match the actual content This was the result of a copy paste.

auto-upgrade: add an option to silence the share-safe message For well tested case, the message can get in the way, so we add a way to disable it.