New SideNav structure

[Mil4n0r]

Checklist

• [ ] Build process is done without errors. All tests pass in the /lib directory.
• [ ] Self-reviewed the code before submitting.
• [ ] Meets accessibility standards.
• [ ] Added/updated documentation to /website as needed.
• [ ] Added/updated tests as needed.

Description The previous HTML structure of the SideNav was very poor in terms of semantics.

Closes #1642

[Mil4n0r]

Required feedback from the rest of the team.

There is still one problem to address. Section compound component is now treated as a ul, however, there are some scenarios where its child is a paragraph or any other text. In my opinion, we should create a specific compound component regarding that scenario. (For example TextSection) in case we don't want to lose that functionality, another more opinionated option would be to simply force the user to use list items as children. (Which is generally the correct case scenario for a SideNav)

[Mil4n0r]

Closed for now until the topic is discussed.