feat(ng/filter): support ASP.NET JSON dates

    Add support for ASP.NET JSON dates. The default JSON serializer
    in the ASP.NET framework serializes dates in the following way:
        "/Date(1198908717056)/"
    This PR allows the date filter to properly format and display
    these dates. A test case and documentation were also added.
    
    This PR should not break anything, only add additional features.

I also changed the timezone of my computer to make sure that the test
runs properly in different time zones, and it seems to be the case.