Foldering mechanism overhaul

[RealmX1]

For foldering mechanism in the notabase to be preserved during export, and interpreted during import, one thing need to be addressed:
Currently in exported files, if you have note titled "A/B", it will be interpreted as folder A note B in the export file. so no real implementation of preservation of foldering mechanism exist at the moment.



(which might require an overhaul of the way notes are stored; potentially by wrapping actual note in the .md)

Its not essential, but to the very least, helps with migrating notes, and encourages users from other note applications to switch to notabase.