implement {colorspace} key for burnins

[MustafaJafar]

Changelog Description

resolve #1372

Additional Info

The {colorspace} in this context is resolved to the target colorspace.
We may need to add support for the source colorspace which may need another PR to add the source colorspace to the collected data as the colorspace data that is available atm are

{
    "colorspace": "Output - Rec.709",
    "config": {
        "path": "E:\\Ynput\\ayon-ocio\\client\\ayon_ocio\\configs\\OpenColorIOConfigs\\aces_1.2\\config.ocio",
        "template": "{BUILTIN_OCIO_ROOT}/aces_1.2/config.ocio"
    }
}

Also, the source colorspace key may not be needed as this PR #1268 suggests colorspace key for source colorspace and targetOCIOColorspace key for the target colorspace if I'm not mistaken.

Demo

Testing notes:

1. {colorspace} should work in burnin settings.

[MustafaJafar]

Note: I made this PR to share my finding. I'm not sure if this is the proper solution.

[jakubjezek001]

This is very good point, we have to find a way to add colorspace name into burnins. But this is quite difficult as you had described in the PR description. Not even source and target colorspace would help. Here is a example of flow where source and target colorspace wouldn't work either:

colorspace: representation colorspace reflecting current data colorspace
source colorspace: trancoding colorspace-in value, usually used from representation colorspace key value
target colorspace: trancoding colorspace-out value, usually will become new representation colorspace key value

nuke ExtractRender write node: EXR (colorspace: ACEScg)
ExtractReview: MP4 (source colorspace: ACEScg, target colorspace: Output - sRGB, colorspace: Output - sRGB)
ExtractBurnins: MP4 (source colorspace: Output - sRGB, target colorspace: Output - sRGB, colorspace: Output - sRGB)

Notice one thing. The burnin representation will have all colorspace values set to Output - sRGB. But althought it is correct still it feels off, right. I am assuming most of clients would rather see the original product's main representation colorspace. So in our case it would be rather ACEScg.

So we should find a better way to store full history of colorspace flow and for this burnin to use the first captured colorspace used.