[Feature request] Folder settings - additional default options

[TheTomato18]

An additional default option where if a folder setting is left blank, will defer to (or create) a deck to the current folder and if there are parent folders, under them as well. For example:

'First_Folder\Second_F\Third_F\Note.md'

And the flashcards are exported to Anki under the deck 'Top_Folder::Second_F::Third_F'.

For users like myself with lots of folders, this is a lot more convenient!