* Convert `RouteValueDictionary` values to `string` using `CultureInfo.InvariantCulture`
- #8578
- user may override this choice in one case:
- register a custom `IValueProviderFactory` to pass another `CultureInfo` into the `RouteValueProvider`
- values are used as programmatic tokens outside `RouteValueProvider`
nits:
- take VS suggestions in changed classes
- take VS suggestions in files I had open :)
