Ability to change local save directory

[Borsas]

I didn't like that sharenix defaults local saves to /home/user/sharenix and doesn't organize the files by month so i added the ability.

This was my first time coding in Go, so please bear with me.

[Francesco149]

good idea, however there's a few issues with the implementation

• sharenix -history can't find the csv anymore
• without the origanized folders, it doesn't create an "archive" subfolder like before

I'll fix these in a minute...