Add initial implementation of the mkdocs-color-swatch-plugin

[fabieu]

This pull request introduces a new MkDocs plugin, mkdocs-color-swatch-plugin, which allows users to add inline color swatches to their Markdown documentation. The changes include the implementation of the plugin, its supporting assets, workflows for testing and publishing, and updates to documentation and configuration files.

Plugin Implementation:

• mkdocs_color_swatch_plugin/plugin.py: Implements the ColorSwatchPlugin class, which integrates the plugin into MkDocs. It handles the injection of CSS and JavaScript assets and registers the ColorSwatchExtension for Markdown processing.
• mkdocs_color_swatch_plugin/color_swatch.py: Defines the ColorSwatchExtension and ColorSwatchInlineProcessor to parse and render custom Markdown syntax for color swatches.

Supporting Assets:

• CSS (mkdocs_color_swatch_plugin/assets/color-swatch.css): Provides styles for the color swatches, including hover animations and tooltips.
• JavaScript (mkdocs_color_swatch_plugin/assets/color-swatch.js): Adds interactivity for copying color codes to the clipboard and displaying toast notifications.

Workflow and Configuration:

• Workflows (.github/workflows):
  • build.yml: Automates the build, test, and publish process for the plugin.
  • test.yml: Runs tests using pytest on pull requests and manual triggers.
• Configuration Files:
  • pyproject.toml: Defines the project metadata, dependencies, and entry points for the plugin.
  • mkdocs.yml: Configures the demo site for the plugin.

Documentation:

• README.md: Provides an overview of the plugin, including features, installation instructions, syntax usage, and contribution guidelines.
• Demo (docs/index.md): Demonstrates the plugin's functionality with sample color swatches.