OpenVR in Guix

[Tobias Platen]

I saw that Guix includes OpenVR[1], which is kind of problematic,
because there is no libre compatible runtime. I have a Valve Index,
which I use without Steam[2], using the libre runtime Monado, which
currently only supports OpenXR[3], but I plan to add a nonsteam OpenVR
runtime to Monado. So I think there is no need to remove OpenVR.
In Debian this packages is in contrib, because of the SteamVR
dependency.

[1]https://guix.gnu.org/en/packages/openvr-1.8.19/
[2]https://www.gnu.org/philosophy/nonfree-games.html
[3]https://guix.gnu.org/en/packages/openxr-1.0.24/