Optimize award_program_certificates task
Optimize award_program_certificates task

More than 70% of the execution time is spent in CPU. The change of
query is to avoid the massive course_id__in the GeneratedCertificate
was doing on CourseOverview

PROD-67

angelapper/edx-platform,EDUlib/edx-platform,angelapper/edx-platform,arbrandes/edx-platform,jolyonb/edx-platform,msegado/edx-platform,edx-solutions/edx-platform,EDUlib/edx-platform,angelapper/edx-platform,edx-solutions/edx-platform,EDUlib/edx-platform,appsembler/edx-platform,arbrandes/edx-platform,edx-solutions/edx-platform,msegado/edx-platform,edx-solutions/edx-platform,eduNEXT/edx-platform,EDUlib/edx-platform,jolyonb/edx-platform,arbrandes/edx-platform,stvstnfrd/edx-platform,mitocw/edx-platform,ESOedX/edx-platform,cpennington/edx-platform,edx/edx-platform,stvstnfrd/edx-platform,appsembler/edx-platform,mitocw/edx-platform,mitocw/edx-platform,stvstnfrd/edx-platform,ESOedX/edx-platform,eduNEXT/edunext-platform,jolyonb/edx-platform,appsembler/edx-platform,jolyonb/edx-platform,ESOedX/edx-platform,cpennington/edx-platform,appsembler/edx-platform,msegado/edx-platform,arbrandes/edx-platform,eduNEXT/edx-platform,cpennington/edx-platform,stvstnfrd/edx-platform,mitocw/edx-platform,eduNEXT/edunext-platform,msegado/edx-platform,msegado/edx-platform,angelapper/edx-platform,eduNEXT/edx-platform,eduNEXT/edx-platform,edx/edx-platform,eduNEXT/edunext-platform,edx/edx-platform,eduNEXT/edunext-platform,edx/edx-platform,ESOedX/edx-platform,cpennington/edx-platform