add export/import whole config+database option

For some users, changing PC is really complicated as they do not find easily their user preference folder or don't know how to tranfer them.

I had 2 cases on the forum, one under linux (dotfiles hidden in file browser) and one under windows (Local Settings or AppData are hidden by default)

It would be helpful to have somewhere an option to fully export the database+configuration files as a zip file and another one to import the zip file on the new computer.

this way, the only thing left to the user is to tranfer the music files, which is pretty easy.