Add Display description to OCIO configs

With OCIO v2 we now have a description field in the View specification, maybe it would be interesting to have a corresponding field for the display itself. An example use case would be a DCC with separated list to pick Display and View, each having a tooltip. Sometime the display name is not enough to really know what is the actual calibration target (example being ACES configs with the `P3-D65 - Display`, we also sometime use display names in our internal configs that are meant to be easy to use for non colour savvy artists but more advanced users usually want more information).

With the current OCIO YAML structure it looks like this would not be straightforward to add.