window: Rework widgetry

[BrainBlasted]

• window: Rework widget hierarchy
• window: Make searchbar a ToolbarView top bar
• window: Use bidirectional property binding for search
• window: Simplify and sync sensitivity
• window: Add status pages for search/no voices

[eeejay]

This PR is amazing! Thank you for working on this. Can you please format with black and push?

[BrainBlasted]

Done :)

[eeejay]

than you!