Add option to disable previews

Is your feature request related to a problem? Please describe.
I have previews enabled in my nextcloud instance, but I don't want that the previews are shown in the viewer app. I need to have it enabled for other purposes (e.g. the memories app), so just disabling previews for the whole nextcloud instance isn't a solution for me. When I want to scroll through my photos and view some of them, I'm using the memories app (which first shows the preview and then loads the full size photo). However, when I open a photo through the files app (which opens it in this viewer app), I also want to be able to see the full size photo without having to download it.

Describe the solution you'd like
I would like to have a configuration option to ignore the previews. If that option is enabled, the viewer app should always load the full size photo like when previews are completely disabled for the whole nextcloud instance.

As an alternative, the viewer app could first load the preview and then load the full size image, similar to how it's done in the memories app.

Start in the viewer app's preview-loading path and trace how files opened from the files app select preview or full-size media. Compare the requested behavior with the Memories app's loading sequence. Done means a viewer configuration option can bypass previews and load the full-size photo, or consistently loads the preview before the full-size image.