feat: add UI features/options: hide/show/toggle/resize elements

[gacallea]

better UI experience, without losing its content:

• [ ] toggle UI entirely
• [ ] toggle single panes
• [ ] resize panes

[gacallea]

after trying to implement a sane way to maange this, I concluded: won't fix. the webchuck ui is great enough.

[gacallea]

ps: unless someone can help on this.