intellij-style, side-locked dockers and ui cleanup

[ix0rai]

about ready for testing, so I'm drafting this here!

changelog:

• dockers!
  • dragged around via their title
  • can be docked in 6 different locations
  • 4 dockers can be on the screen at once (+1 from previous maximum amount of visible side panels!)
  • minimise button to close
  • docks will highlight the future location of the docker when hovered while dragging a docker label
• new panel: all classes
  • replaces the old --single-class-tree option for viewing both deobf and obf classes in one panel
• add "start server" and "connect to server" buttons to collab panel when offline, for convenience
• remove a bunch of dead code
• cleanup and style enforcement

todo

• testing and bugfixing
• closing docker panels when empty
• improving intuitiveness of moving things around
• translation migrations
• make it more obvious that docker titles are what you should drag to move panels
• configurable highlight colour
• add "all classes" docker
• reimplement --single-classes-panel command line option
• custom hover and drag cursors for draggable labels

notes:
builds off #23 and is a quilt equivalent of FabricMC/Enigma#420
fixes #25
this could be a good opportunity to introduce a "partially deobfuscated classes" docker, similar to FabricMC/Enigma#482, although I'd prefer to do that in a separate PR

[IotaBread]

The only issues I could find now

• Dock resizing doesn't work unless you minimize the resized docker before changing to a new one, within the same dock

• In some cases, dock sizing may become inconsistent

  Reproduction steps:

  1. Launch Enigma
  2. Open a docker the left and right
  3. Minimize all dockers on the right
  4. Minimize all dockers on the left
  5. Open a docker on the right
  6. It's width is now different from the previous one