Permissions - WIP

- [x] Implement makeReadOnly/makeEditable interface for EditorPane.
- [x] Implement makeReadOnly/makeEditable interface for TerminalPane.
- [x] Implement makeReadOnly/makeEditable interface for DrawingPane.
- [] Implement makeReadOnly/makeEditable interface for file tree.
- [] Sync host file tree interactions like folder open/close to participants.
- [] Disable or visually hide `+` handle in IDEViews.
- [] Write participants initial permission state to RealTimeDocument.
- [] Update participant permission state after host change.
- [] Apply new participant permission for that participant.