For test purpose it's useful to run open-source IPA modules in isolation. This can already be done by deleting the corresponding signature file, but that method can be inconvenient. Add a way to force IPA module isolation through a new LIBCAMERA_IPA_FORCE_ISOLATION environment variable. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com> Reviewed-by: Umang Jain <umang.jain@ideasonboard.com> Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>