[FEATURE REQUEST] Integration with Paperless NGX

Hello developer team!

Thank you very much for this project!

Is your feature request related to a problem? Please describe.

Not related to a problem, but a dream: I'm using Paperless NGX, which is a wonderful backend to store scanned documents. So far I've been using Paperless mobile, which is a nice Android client, but sadly lacks a bit behind in active development (not sure, with I think I saw the developer telling this in as issue, too). Then there is OSS Document Scanner. From my perspective it could be a good replacement to Paperless mobile, if it would support the backend as a default storage location. I've seen you've been considering this yet. You were stating that the API is missing an option to update existing documents.

Describe the solution you'd like

I wish the integration could be taken into account again. Maybe without that special API endpoint in the first milestone. A simple upload as a default storage location would be perfectly fine for me (and I guess for many other users too). Together, your project could build up a beautiful ecosystem for free and libre document scanning!

Describe alternatives you've considered

I saw that you've already implemented a sharing target for Paperless mobile.

Additional context

The client implementation for the backend API can hopefully be taken from the Paperless mobile app as a starting point. So you don't need to start from scratch. It'll nevertheless probably need some polish as time passes.

Start by reviewing the Paperless mobile API client mentioned in the issue and the prior discussion about the missing update endpoint. Define the first milestone around uploading scans to Paperless NGX as a storage location, then verify that a scan can be uploaded successfully through the integration.