With the new ui, the footer and legal pages
are no longer needed.
This commit removes them.

useResponsiveStore is a hook store that provides
the current screen size and the current device type.

Update header ui to match the new design:
- Remove Marianne
- Smaller header
- Remove some borders

Update doc header ui to match the new design:
- Remove tag about visibility
- Remove dates
- Remove owners
- Remove your roles
- Take less place

We have to adapt the table of content to the new ui.
It is now totally on the right side of the screen.

We slightly adapt the docs list to the new ui.

We adapt the header to be small mobile friendly.
We added a burger menu to display the dropdown
menu on small mobile.

Reduce the font size of the BlockNoteEditor
to make it mobile friendly when the screen is small.