Content browser continuation

[FacoBackup]

• [x] Directory tree
• [x] Directory navigation
• [x] path search implementation
• [ ] Back/Forward actions
• [x] Icons for directories and files
• [ ] Option for creating file
• [ ] Context menu for deleting or renaming (modal)
• [x] onContextChange
  • [x] on set context, add panel to list of listeners inside context object
  • [x] after context state change, a method in the context object should be called that will trigger all panels that are included in the list
  • [x] ~Override method inside abstract panel for on context change~
• [ ] Limited scope to project folder
• [ ] Path search begins at the project root
• [ ] Import file with native file picker
• [x] Async fs read operations