This change removes the IActionContextAccessor as a dependency of
UrlHelper, and shifts UrlHelper to use a factory pattern. Consumers of
IUrlHelper should create an instance using the factory when needed.
This is the last part of MVC that has a dependency on IActionContext
accessor. As part of this change we no longer register it by default, and
treat it as an optional component.
Ryan Nowak
Pranav K
Chris R