WIP: 2.0 release

[DaGhostman]

• [x] Major code base improvements [BC]
  • [x] Centralized handling of icons and "jump" commands (via TreeView.getTreeItem)
  • [x] Split tokens in separate files
  • [x] Take advantage of contextValues to menus allow for menus on tree nodes
  • [x] Global handling of readonly & final members and classes
  • [x] Introduce value objects that extend TreeItem to provide cleaner configuration
  • [x] 2 new icons (for interface and trait definitions)
  • [x] Generate interfaces and skeleton implementations from class and interface tree items (context menu)
  • [x] Java support (thanks to #22)
  • [x] Provide symbol tree
  • [x] Extract interfaces & generate skeleton classes
  • treeview.js.readonlyCharacter is now treeview.readonlyCharacter as readonly is treated the same way as final [BC]
  • [x] Extraction and generation
  • [x] Handle abstract definitions
  • [x] Handle static definitions

• More TBD