Integrate Material for Mkdocs functionalities

[me-pic]

Integrate Material for Mkdocs to change the layout / rendering of the current website

Detailed Description

• Improve the navigation on the website by displaying overall sections structure on the left of the webpage and the table of content of each section on the right (see example: https://squidfunk.github.io/mkdocs-material/setup/setting-up-navigation/)
• Re-structure the content of the section with collapsable sub-sections (see example: https://squidfunk.github.io/mkdocs-material/setup/setting-up-navigation/#navigation-sections)
• Add dark mode

Context / Motivation

• It would make the content of the website more digestible by avoiding long page of content
• That configuration would also be more convient for the upcoming updated version of the contributor's guide that @m-miedema is working on

• A lot of people appreciate the dark mode

Possible Implementation

https://github.com/me-pic/physiopy.github.io/tree/ENH/layout