PR: Prepare Project for First Release

[KelSolaar]

Summary

This PR prepares the project for a first release:

• The latest colour check configuration has been applied.
• Typing annotations have been extended.
• Documentation and docstrings have been updated.
• Some breathing/line breaks have been added to the code.
• colour_clf_io.ExponentStyle, colour_clf_io.LogStyle and colour_clf_io.RangeStyle enumerations were moved to the colour_clf_io.values module.
• Ensured that the project builds.
• Ensured that the docs are building: https://colour-clf-io.readthedocs.io/en/latest/
• Updated the Github templates.

A few notes collected whilst doing this:

• A few places should have default values, e.g., colour_clf_io.SOPNode.slope but we do not set any.
• colour_clf_io.parsing.child_elements returning str is a major pain for type checking, we should look at a way of making sure that contextually, it only returns lxml.etree._Element | None. I peppered the code with Pyright pragmas for now.
• Should colour_clf_io.ProcessNode.description be a list[str] like colour_clf_io.ProcessList.description?

Preflight

Code Style and Quality

• Unit tests have been implemented and passed.
• Pyright static checking has been run and passed.
• Pre-commit hooks have been run and passed.

Documentation

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