Summary

This PR implements support to load environment variables from a file.

It is now possible to create a ~/.colour-science/colour-science.jenv JSON file from which Colour will load environment variables from:

{
  "COLOUR_SCIENCE__COLOUR__SHOW_WARNINGS_WITH_TRACEBACK": 1
}

The following new environment variables are now supported:

COLOUR_SCIENCE__FILTER_RUNTIME_WARNINGS: Filter Colour runtime warnings.
COLOUR_SCIENCE__FILTER_USAGE_WARNINGS: Filter Colour usage warnings.
COLOUR_SCIENCE__FILTER_COLOUR_WARNINGS: Filter Colour warnings, this also filters Colour usage and runtime warnings.
COLOUR_SCIENCE__FILTER_PYTHON_WARNINGS: Filter Python warnings.

This should help with #1221 and #1237.

Preflight

Code Style and Quality

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

Documentation