refkit-image.bbclass: flatpak-enabled images, enable flatpak repo support.
refkit-image.bbclass: flatpak-enabled images, enable flatpak repo support.

If meta-flatpak is available and the DISTRO_FEATURE is on inherit
flatpak-image-variant and flatpak-repository to enable building
flatpak-enabled images and generating corresponding flatpak repositories.

Signed-off-by: Krisztian Litkey <712507b69edd1d51f7fea367c223b6763c574209@iki.fi>

YinThong/intel-iot-refkit,mythi/intel-iot-refkit,jairglez/intel-iot-refkit,ipuustin/intel-iot-refkit,klihub/intel-iot-refkit,mythi/intel-iot-refkit,klihub/intel-iot-refkit,ipuustin/intel-iot-refkit,klihub/intel-iot-refkit,klihub/intel-iot-refkit,klihub/intel-iot-refkit,jairglez/intel-iot-refkit,YinThong/intel-iot-refkit,ipuustin/intel-iot-refkit,jairglez/intel-iot-refkit,mythi/intel-iot-refkit,mythi/intel-iot-refkit,YinThong/intel-iot-refkit,jairglez/intel-iot-refkit,mythi/intel-iot-refkit,jairglez/intel-iot-refkit,intel/intel-iot-refkit,ipuustin/intel-iot-refkit,ipuustin/intel-iot-refkit,intel/intel-iot-refkit,YinThong/intel-iot-refkit,mythi/intel-iot-refkit,intel/intel-iot-refkit,klihub/intel-iot-refkit,YinThong/intel-iot-refkit,jairglez/intel-iot-refkit,intel/intel-iot-refkit,klihub/intel-iot-refkit,intel/intel-iot-refkit,YinThong/intel-iot-refkit,ipuustin/intel-iot-refkit,ipuustin/intel-iot-refkit,mythi/intel-iot-refkit,YinThong/intel-iot-refkit,intel/intel-iot-refkit,jairglez/intel-iot-refkit,intel/intel-iot-refkit