Feature parity with old Cavalier

[fsobolev]

• Drawing modes (Drawing modes and settings #4)

  • Wave
  • Levels
  • Particles
  • Spine
  • Bars

• Area settings (Drawing modes and settings #4)

  • Margin (Window settings #2)
  • Offset between items
  • Roundness of items
  • Filling
  • Thickness of lines

• Window settings (Window settings #2)

  • Borderless
  • Sharp corners
  • Show/hide window controls
  • Autohide header

• CAVA settings (CAVA settings #3)

  • Number of bars
  • Autosens
  • Manual sensitivity
  • Channels
  • Smoothing
  • Noise reduction
  • Reverse order

• Widgets style toggle (Color Profiles and old translations #9)

• Color profiles (Color Profiles and old translations #9)

• Copy old translations (Color Profiles and old translations #9)

• Keyboard shortcuts (Keyboard shortcuts and various fixes #11)

Import/export doesn't make sense now since settings will be stored in JSON, and so can be easily copied.
A mechanism to automatically import old values from GSettings if JSON file doesn't exist would be nice.