Add NeosDocumentImport family

[mpmxyz]

This time it is 3 mods in one repository to allow document import conversions:
1x library mod
2x miniature mods that register their conversion code using the library
PS: Visual Studio broke formatting while editing the JSON. -> pls squash the extra commits

[XDelta]

You do not need merge master branch after making the pr, unless you make actual changes to the pr afterwards, this will be done by the reviewer.

[ljoonal]

Not sure, but think it'd make sense to separate the libs into their own entries like has been done with harmony...

[mpmxyz]

I'm looking into it. It is inconvenient having to take care of transitive dependencies. Luckily it isn't many.
I'll probably use this opportunity to change to a pdfium binding that is receiving updates. (e.g. PdfLibCore)

[mpmxyz]

I finished changing my project and fleshing out the manifest changes.
Now every external dll has it's own entry in the manifest.
I do not know how to get a url to dll files of NuGet packages. So I kept referencing to my own artifacts.