Solid Symposium release

[timea-solid]

A ticket with open tasks to do before we release for the Solid Symposium:
Deadline 24th April. (release can occur sooner)

Solid-panes:

• make left side menu foldable and only show icons
• improve left side menu to adhere to mobile design
• add footer to left side menu - @timea-solid
• make left side menu not scroll
• make sure left side menu items work when not logged in (also when logged in)
• hide complex panes under Power User
• fix look of Social Pane

solid-ui

• streamline usage of theme and icons, as much as possible

Mashlib

• clarify font in use
• fix browse.html
• test how the overall look is

Final steps:

• Test on testservers
• Implement any feedback
• Release all repos from milestone3m branch
• Release final Mashlib for Solid Symposium

Bonus steps - not important for Solid Symposium:

• make sure mashlib looks good on mobile too
• make sure solidOs from branch milestone3m works
• Decide and create a new theme repository -> @timea-solid
• Move new design icons to new repository (copy from profile-pane) -> @timea-solid
• Release new theme repository (npm package style)
• Use new design icons in code where needed for symposium (profile-pane, solid-ui, solid-panes...)
• Display Storage also when not logged in but only display public containers and content

[timea-solid]

In solid-panes we now have:
Left side menu shows Profile and Friends when loggedin or not. Storage and the other menu item are only shown if one is logged in and some only when one is powerUser.
Notice: in the design, Storage is called Dashboard -> not sure about this, we keep it storage for now. I do not display Storage when not logged in because this needs more work which I am not sure we have now.