Config: Disable any use of libvips with `PHOTOPRISM_DISABLE_VIPS`

[lastzero]

As an admin, I want to be able to disable any use of libvips with a single config option so I don't need to search for all related options and disable them individually.

Related Issues:

• Colors: Add libvips support to preserve ICC profiles in thumbnails #1474
• Config: Disable all backups with PHOTOPRISM_DISABLE_BACKUPS #4294