Create large-image tiles in a job instead of on every upload request

[romleiaj]

girder_large_image's auto-set runs createImageItem synchronously when each file is saved, so every uploaded or imported image -- including JPG/PNG frames of plain image sequences, which never use tiles -- was probed for a tile source inside its own upload request. On a multicam flight with thousands of frames per camera, uploads queued behind that work until requests hit the gateway timeout.

The DIVE plugin now defaults large_image.auto_set to off (an explicit admin setting still wins). postprocess queues a create_large_image_tiles job when a folder holds large-image files (TIFF, NITF, ...) that have no tiles yet; the job creates them one item at a time with progress and marks the folder as a dataset when done. Uploads and filesystem/S3 imports both reach postprocess, so both are covered. The existing per-item tile check is shared with convert_large_images.

The multicam upload's wait for camera processing now restarts its 10-minute clock whenever a job reports progress, so a long tiling job that keeps moving is not cut off.