PR: Implement support for "ARRI Wide Gamut 4" and "ARRI LogC4".

[KelSolaar]

Summary

This PR implements support for ARRI Wide Gamut 4 and ARRI LogC4.

The existing ALEXA Wide Gamut colourspace and ALEXA LogC log encoding have been renamed to ARRI Wide Gamut 3 and ARRI LogC3 respectively.

@JGoldstone for VIS.

Preflight

Code Style and Quality

• Unit tests have been implemented and passed.
• Mypy static checking has been run and passed.
• Pre-commit hooks have been run and passed.
• [N/A] New transformations have been added to the Automatic Colour Conversion Graph.
• New transformations have been exported to the relevant namespaces, e.g. colour, colour.models.

Documentation

• New features are documented along with examples if relevant.
• The documentation is Sphinx and numpydoc compliant.

[coveralls]

Coverage increased (+0.0005%) to 99.808% when pulling 5a97084 on feature/arri_logc_4 into 065c3a6 on develop.

[KelSolaar]

@nick-shaw, @scoopxyz : Be glad if you could drop a quick eye on this one, keen to merge it to get going on 0.4.2 release.

Cheers,

Thomas

[KelSolaar]

Been two weeks, I will merge this one!