Added refresh_course_metadata management command

This command will call the data loaders, and update the course metadata.

ECOM-3765

course_discovery/apps/course_metadata/management/commands/refresh_course_metadata.py

+import logging
+
+from django.conf import settings
+from django.core.management import BaseCommand
+from edx_rest_api_client.client import EdxRestApiClient
+
+from course_discovery.apps.course_metadata.data_loaders import OrganizationsApiDataLoader, CoursesApiDataLoader
+
+logger = logging.getLogger(__name__)
+
+
+class Command(BaseCommand):
+    help = 'Refresh course metadata from external sources.'
+
+    def add_arguments(self, parser):
+        parser.add_argument(
+            '--access_token',
+            action='store',
+            dest='access_token',
+            default=None,
+            help='OAuth2 access token used to authenticate API calls.'
+        )
+
+    def handle(self, *args, **options):
+        access_token = options.get('access_token')
+
+        if not access_token:
+            logger.info('No access token provided. Retrieving access token using client_credential flow...')
+
+            try:
+                access_token, __ = EdxRestApiClient.get_oauth_access_token(
+                    '{root}/access_token'.format(root=settings.SOCIAL_AUTH_EDX_OIDC_URL_ROOT),
+                    settings.SOCIAL_AUTH_EDX_OIDC_KEY,
+                    settings.SOCIAL_AUTH_EDX_OIDC_SECRET
+                )
+            except Exception:
+                logger.exception('No access token provided or acquired through client_credential flow.')
+                raise
+
+        OrganizationsApiDataLoader(settings.ORGANIZATIONS_API_URL, access_token).ingest()
+        CoursesApiDataLoader(settings.COURSES_API_URL, access_token).ingest()