Collapsible Sidebar + UI Layout Rework

[LinuxinaBit]

I've felt for a while that MeshChat needs a less cramped UI:

Current default

I think this layout , with the header-bar removed, or something similar could be a good solution:

New default (First launch)

There's now a surprising amount of extra vertical space, allowing much more of the NomadNet page or conversation to be onscreen at once...

Note that here the sync and compose buttons could be moved down to just above the quick settings, depending on design preferences. This is merely a concept.

Collapsed

This allows for much wider windows, meaning we can finally properly view the ASCII art!

Collapsing the sidebar would ideally be persistent across app restarts.

An Android style slide-over sidebar is also likely necessary for smaller screen sizes (<=720p for ex. a small Raspberry Pi display), and for possible future mobile UI ports.

I would love to do this myself, but the understanding the full effects of editing these funky CSS classes is beyond my current ability :/