…PI as experimentalThis publishes the work that was done to integrate with the NavigationAPI as an experimental router feature. Browser support is limited and inactive development. There are also known bugs in the browser implementationsand only Chromium browsers supported deferred URL updates with the`precommitHandler`. Relates toangular#53321, which I would likely not mark ascompleted until this is at least in dev preview, which likely won'thappen until it is widely available and potentially delayed until`precommitHandler` is widely available as well.The final form of this api might not even be a "router feature" in the end, but instead besomething similar to what other frameworks have to provide differentplatform integrations (e.g. `provideNavigationRouter`). That wouldsupport omitting the history-based integration from the bundle when onlythe navigation integration is used. Alternatively, the current`provideRouter` could require one of `withHistory` or `withPlatformNavigation`.