Heiholf

Added thumbnail rendering for PDF-files

1

Adds thumbnail support for PDF files as proposed in #374. Uses Qt's inbuilt PDF renderer. One thing which is kind of weird is the arbitrary scaling of the image with...

[Feature Request]: Add general thumbnail support for file types with thumbnails in zip file (i.e. Libre-/OpenOffice)

2

### Checklist - [X] I am using an up-to-date version. - [X] I have read the [documentation](https://github.com/TagStudioDev/TagStudio/blob/main/doc/index.md). - [X] I have searched existing [issues](https://github.com/TagStudioDev/TagStudio/issues). ### Description LibreOffice files only show...