What is csc.rsp file and How can I add it to Unity assest?

Hi, I am new to the Unity, I want to use the MediaPlayer class in PresentationCore.dll to run in Microsoft Hololens. However, currently, I am experiencing trouble, how to import this assembly to Unity?. In Unity manual I saw that, (https://docs.unity3d.com/Manual/dotnetProfileAssemblies.html) we can include it using a csc.rsp file, but I do not have any idea how to add this file into Assets in Unity? Further, I want to know whether I can use the MediaPlayer class in Unity, as Unity provides its own VideoPlayer class and I could not see any sample application using MediaPlayer class along with Unity to be used with Windows device. Thank you.