VJOURNAL: initial support

See #728581

- VJOURNAL ("memos") notes from evolution accounts are
  automatically shown
- They appear on the bottom (date is not handled)
  User can amend notes.
- Categories is not supported yet
- A crash occurs if an Ical is set as default storage
  and new notes is asked.
  Because it is not implemented.
- Saving note does not damage attachments and so on