Add support for migrating old buffer file to new library.
Add support for changing location for the notes library.
Replace theme toggle in status bar with a dropdown in Appearance settings.
Improve New Note and Update Note dialogs.
Implement UI for confirming note delete (the actualal deltion is still to be implemented).
Refactor Vue <-> Editor <-> CodeMirror code.
Introduce Pinia store to keep global state, in order to get rid of a lot of event juggling between Editor class/child components and the root App component.
