disable course discovery feature by default in devstack.
disable course discovery feature by default in devstack.

appsembler/edx-platform,edx-solutions/edx-platform,openfun/edx-platform,appsembler/edx-platform,cecep-edu/edx-platform,cecep-edu/edx-platform,marcore/edx-platform,marcore/edx-platform,openfun/edx-platform,chand3040/cloud_that,edx-solutions/edx-platform,marcore/edx-platform,chand3040/cloud_that,appsembler/edx-platform,cecep-edu/edx-platform,chand3040/cloud_that,edx-solutions/edx-platform,chand3040/cloud_that,marcore/edx-platform,appsembler/edx-platform,gymnasium/edx-platform,edx-solutions/edx-platform,gymnasium/edx-platform,openfun/edx-platform,cecep-edu/edx-platform,openfun/edx-platform,chand3040/cloud_that,cecep-edu/edx-platform,gymnasium/edx-platform,gymnasium/edx-platform,openfun/edx-platform