Shows relationships between color spaces and explains what files should
contain which conversions.
# Objective
- Provide documentation for maintainers and users on how color space
conversion is implemented.
## Solution
- Created a mermaid diagram documenting the relationships between
various color spaces. This diagram also includes links to defining
articles, and edges include links to conversion formulae.
- Added a `conversion.md` document which is included in the
documentation of each of the color spaces. This ensures it is readily
visible in all relevant contexts.
## Notes
The diagram is in the Mermaid (`.mmd`) format, and must be converted
into an SVG file (or other image format) prior to use in Rust
documentation. I've included a link to
[mermaid.live](https://mermaid.live) as an option for doing such
conversion in an appropriate README.
Below is a screenshot of the documentation added.
