Add a virtual_display to the ACES configs

[doug-walker]

The virtual_display is used to define the set of views that should be added if a new SDR display is added to the config from an ICC profile.

The contents would be the same as the existing displays such as sRGB and Rec.709:

virtual_display:
    - !<View> {name: Raw, colorspace: Raw}
    - !<Views> [ACES 1.0 - SDR Video, ACES 1.0 - SDR Video (D60 sim on D65), Un-tone-mapped]

[doug-walker]

Here is some Python code to implement this:

    # Copy all shared views from a reference display (could be any SDR display).
    ref_display = 'Rec.1886 Rec.709 - Display'
    for view_name in config.getViews(ocio.VIEW_SHARED, ref_display):
        config.addVirtualDisplaySharedView(view_name)

    # Add Raw, which is not a shared view in the ACES configs (though it could be).
    config.addVirtualDisplayView(view="Raw", viewTransformName="", colorSpaceName="Raw",
        looks="", ruleName="", description="")

[KelSolaar]

Do we want this for all the SDR / HDR displays or only the SDR ones? Op seems to indicate this would be only for the SDR.

[doug-walker]

The intent was SDR-only -- the virtual display is intended to be used with ICC profiles, which currently only support SDR.

[doug-walker]

Validated this as completed in the current config draft:

virtual_display:
  - !<View> {name: Raw, colorspace: Raw}
  - !<Views> [Un-tone-mapped, ACES 2.0 - SDR 100 nits (P3 D65), ACES 2.0 - SDR 100 nits (Rec.709)]

Note that this is following "P3-D65 - Display" rather than "Rec.1886 Rec.709 - Display" but I think that is better since we don't know the gamut of an arbitrary ICC profile, so it's better to offer both target gamut options.

[doug-walker]

Implemented in PR #160.