Ability to synchronize books (incl. progress) between devices

[k-kolev1985]

Is your feature request related to a problem? Please describe.

If I want to use Bookworm on more than one computer, I can do that. But as far as I know, at the moment I cannot synchronize my book reading progress between the different computers.

Describe the solution you'd like

Maybe providing an option in Bookworm to save the currently read book in some specific to Bookworm file format (e.g. XML-based) that contains the book content, the bookmarks, notes, book reading progress, etc. is a good solution as a start. That way we can save our book in this format and transfer it between our computers (e.g. on a flash drive, SD card, cloud storage, etc.). And no matter on which computer with Bookworm installed we open that book file, we can resume reading from where we left off, review our bookmarks and notes, etc.