Allow creating new position folders data struct, see #750

[ElpadoCan]

This PR adds a checkpoint to the data structure module where, if position folders already exist in the destination folder, the user will have the possibility to choose to create new Position folders in addition to overwriting or adding files to existing position folders.

This implements #750

[Teranis]

Not related to the changes here, but maybe we should address this in this PR:
If I select a folder with several raw files, it asks which one should be selected, but pressing ok just ends the process:
Closing data structure logger...

[ElpadoCan]

Not related to the changes here, but maybe we should address this in this PR: If I select a folder with several raw files, it asks which one should be selected, but pressing ok just ends the process: Closing data structure logger...

You mean when selecting "Single microscopy file with multiple positions" and then selecting a folder that contains more than one file?

[Teranis]

I am not entirely sure why (whether it has to do with the conversion itself or this new feature), but for me, after confirming the metadata, it instantly finishes, and no new Pos folders are added, sadly. No error msg

(For completeness reasons, since I put it in the wrong PR 🙃

[ElpadoCan]

We need to test adding positions using the "Single microscopy file with multiple positions" option.

Adding Positions with this option should go through a warning because the user is potentially merging different experiments.

[Teranis]

Will close #73

[ElpadoCan]

The last commit fixes the bug that was preventing creating additional new Positions with the option "Single microscopy file with multiple positions"

[Teranis]

Looking good! (sorry didn't see that it needed my approval, also tested again to be sure)