Merge branch 'Cloudcet_15.0' into 'master'

nextcloud-docker/13.0/Dockerfile

nextcloud-docker/13.0/config/apache-pretty-urls.config.php

nextcloud-docker/13.0/config/apcu.config.php

nextcloud-docker/13.0/config/apps.config.php

nextcloud-docker/13.0/config/autoconfig.php

nextcloud-docker/13.0/cron.sh

nextcloud-docker/13.0/entrypoint.sh

nextcloud-docker/15.0/Dockerfile

nextcloud-docker/15.0/config/apache-pretty-urls.config.php

nextcloud-docker/15.0/config/apcu.config.php

nextcloud-docker/15.0/config/apps.config.php

nextcloud-docker/15.0/config/autoconfig.php

nextcloud-docker/15.0/config/redis.config.php

nextcloud-docker/15.0/cron.sh

nextcloud-docker/15.0/entrypoint.sh

nextcloud-docker/15.0/upgrade.exclude