PR: Implement support for "Munish Ragoo and Farup (2021)" "Optimised IPT" Colourspace.

[KelSolaar]

Summary

This PR implements support for the Optimised IPT colourspace by Munish Ragoo and Farup (2021).

I took that opportunity to refactor most of the IPT-like colourspaces using shared definitions, i.e. colour.models.XYZ_to_Iab and colour.models.Iab_to_XYZ.

References

• https://library.imaging.org/cic/articles/29/1/art00046

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.
• 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 (+0.0006%) to 99.854% when pulling 24656e6 on feature/ragoo2021 into 1a304f6 on develop.