Choose document scan quality

### Is your feature request related to a problem? Please describe.
Currently when scanning documents to PDF, the file size is around 5MB for a single page document (This probably depends on the phone's camera quality settings?). Since i scan very regularly, the 5MB file size adds up quickly.

### Describe the solution you'd like
It would be nice to have an option to choose scan quality to reduce the file size.

### Describe alternatives you've considered
I previously used the iOS app which has a slider to choose scan quality. I often found that I could reduce the quality enough to reduce the PDF file size to around 80KB and still maintain very good PDF readability.

### Additional context
[iOS implementation allows choosing quality level and OCR](https://nextcloud.com/blog/take-your-home-office-anywhere-with-nextcloud-coherence-for-ios-text-recognition-for-scanned-files-and-more/)