feature request: migrate docs generation to mkdocs

Currently, in the template the documentation is generated using Sphinx. However, MkDocs offers a more modern and streamlined approach to documentation generation that could simplify our workflow and provide a better experience for developers and users. Some of the advantages:

MkDocs uses a single mkdocs.yml file for configuration, which is easier to manage and less complex compared to Sphinx’s configuration files (conf.py and others).
MkDocs uses Markdown natively for writing documentation, which is more user-friendly and widely used compared to Sphinx's reStructuredText (.rst).
MkDocs offers a variety of modern themes like "Material for MkDocs", which provide a clean and responsive design out of the box. The plugin ecosystem for MkDocs is robust and growing, with many plugins that can enhance the documentation experience.
MkDocs tends to be faster in generating static sites, which could lead to quicker build times, especially for larger projects.
MkDocs provides built-in support for enhanced navigation, including sidebars and table of contents, and a powerful full-text search, making it easier for users to find information quickly.

NLeSC / python-template

feature request: migrate docs generation to mkdocs #586