
This commit adds a configuration option which must be set in order to enable users to edit their comments, and enable superusers to delete comments. The option, `enable_editable_comments`, is False by default, meaning that the editing and deletion functionality must be opted into. If it is False, then only a database admin can delete or edit comments, by modifying the database directly. Change-Id: Iabf598eae3aa35e4e53aadfe514fb2b0da37cefc