Add feature to choose what to sync on Joplin cloud

[Steph]

In fact tt would be interesting to have, for every note, two little buttons: one to forbid the note to be sync and another to forbid the note to be modify (in local).
Have a look at:

Forbid a note to be modified

It would be useful to have a way to forbid to modify or delete a note... An "lock-unlock" button ? With a message "You are not allowed to modifiy this note" if you try to do it when it's locked. Etc. The goal : to protect MYSELF to modify a note by mistake. If I unlock, i will be able to modifiy again. So : no passwords in this. Why not the same thing for an entire notebook ? Of course, this has nothing to do with the sync process. Thanks !