Create an export/import function.

[AndresMorelos]

As a user, I need to export my invoices, contacts, settings if I want to migrate to another computer; also, I need to import the data to the new computer.

Right now the app is saving the invoices in the indexdb, one solution could be to get all the info and save it as a JSON file to export, and to import the data read a JSON file, and create a new entry for each thing.

Another option could be to implement an API with E2EE in order to let the users sync their data to the cloud.

Refs: https://www.youtube.com/watch?v=VV7x4tMxeoI&ab_channel=yoursTRULY