Fixes OpenXR (#1911)

* Change version of Silk.NET.OpenXR from 2.15.0 to 2.17.1

* using vrFullSurface for Mirror for now

* Improve some Exception and Logging text

* Use XR_REFERENCE_SPACE_TYPE_STAGE as default because standing VR is generally the standard nowadays, rather than seated.

* Deleted deprecated Fove and GoogleVR VirtualReality APIs

* Completely remove Fove & GoogleVR

* Changes OpenVR's default Universe to Standing.

* Set default Universe for OpenVR & OpenXR back to Seated.

* Update all (Stride.Graphics) uses of Silk.NET from 2.15.0 to 2.17.1

* Update System.Memory from 4.5.4 to 4.5.5 to match Silk.NET