Add facing wizard

[Lyrkan]

Another thing I've been working on lately.
Still a WIP but I'd really like to have some feedback about it.

[SergeBakharev]

This is awesome. FYI we had planned to add this functionality a long time ago in #162 with facing being the first example I had in mind. Love to see that you are making it a reality.

[Lyrkan]

Did some tests today and after fixing a few things it should be ready for review!
It's far from perfect but nothing that can't be improved later on.

[Lyrkan]

I added a new commit removing the "Save to file" feature which didn't work on iOS (and maybe also Android... not sure about that one).

I considered just hiding the button on that platform but I also started working on some improvements in #592 (which also needed a file picker) and realized it would be a better idea to just wait for both of them to be merged and add that feature back here in a future PR.

[SergeBakharev]

All good, I believe Software-2 is either working on or planning to soon work on improving file i/o on mobile.

[software-2]

Yep, it's my next feature after some refactoring.