CLC-4091 - Make CSV Enrollment expore executable and add debug logging

https://jira.ets.berkeley.edu/jira/browse/CLC-4091

Adding executable bit to script/export-cached-csv-enrollments-set.sh

Experiencing issues testing in development. The script runs, but execution comes to a halt without any errors logged to explain the halt. Adding verbose debug logging to Canvas::SiteMembershipsMaintainer and Canvas::RefreshAllCampusData to investigate cause of issue.