Vhf2 file format

[daniel-lerch]

This pull request adds a new file format. It does not change the data model.

The new format is easier to debug as it is not encrypted anymore and finally combines the vocabulary book and practice results to a single file. With this change, vhf2 becomes the default file format for Vocup. If a user, however, wants to save a file for an older version, this can be done by save as and selecting the legacy file format.

@jdelange22 please have a look at the dutch translations I created with DeepL. Feel free to comment on everything else as well.

[jdelange22]

Took a quick glance at your code, mostly focussing on the translation. Will dive in deeper when I have more time. I did add some comments.

[jdelange22]

One minor thing that I could think of is this: you've merged the results with the book data. When for example you've created a nice list of want to share this with friends, in the old format you'd only share the words list. But with the new file format you'd also share your practice results right? This isn't a big issue, but have you thought about this?

[daniel-lerch]

One minor thing that I could think of is this: you've merged the results with the book data. When for example you've created a nice list of want to share this with friends, in the old format you'd only share the words list. But with the new file format you'd also share your practice results right? This isn't a big issue, but have you thought about this?

Good point. That was probably the reason for Florian Amstutz (initial developer of Vocup) to store practice results in an additional .vhr file. What do you think about an option in the save as dialog to exclude practice results or do you think adding a separate share dialog would be required?

[jdelange22]

I think the share option fits in this case. The save as dialog is a native Window right? So adding an options there to exclude the results is a bit of work. Also, then you must use the save as option, because just pressing save just writes the practice results. You could also design a custom share dialog that has the option to include the results or not.

[jdelange22]

I commented on your last commit regarding the Dutch translations