SafariView Improvements

[chrisharper22]

Once again, this is a rewrite of the SafariView. This, however, will make the NavigationView push the Safari controller instead of using a sheet (but the latter is still an option). This creates a better UX, as it follows how Safari controllers are presented in other iOS apps. This change does not require changes in pre-existing uses of .safariView(), as it is done all under the hood. (However, because pushing in the Navigation stack does fix the collapsing bar issue (at least on SwiftUI previews?), the SafariView.Configuration used in SettingsAboutView has been modified accordingly).

TL;DR: new default presentation mode for .safariView() because the implementation is re-written

(god please let this be the last time i have to do this pr)