[FEATURE] API: Find trashed files using file-exists endpoint

[JaCoB1123]

My current workflow uses file-exists to check for upload and then uploads the file if it does not exist yet. Unfortunately deleting a file in Docspell, this means file-exists returns nothing again and the file is reuploaded.

Ideally this feature would allow me to move files, that exist in Docspell but have been trashed, to be moved to some other location (i.e. outside my Documents-Inbox). At the moment I have to manually move those files.

I'm using dsc to do my uploading right now, so this also applies there too. Since the API feature is a requirement for dsc, I wanted to check here first if that's an option at all :-)

Thanks!