Improvements to documentation

[luisaFelixSalles]

This issue tracks PyDPF-Core issues related to improvements made to the PyDPF-Core documentation

Documentation system

How should we organize the documentation website?

Sections

• Getting started

• User guide
• Ad an "tutorial" section Add tutorials and update User Guide layout #1749
• Change the main page Adjustments user guide section index page  #1750

• Examples
• Add new subsections in the side bar changes in the sidebar of the examples section #1752
• Reorganize where each example is

• API Reference
• Reconfigure the side bar
• New designs for the cover page of this section

• Operators

• Concepts
• Erase and merge with the user guide section

• Contribute

[luisaFelixSalles]

Layout changes

• Add caption in the toctree for better sidebar design