Easier joining of report types: Currently joins are constructed by embedding one report within another. Provide a new tab allowing commonly desired related tables to be added to a report with predefined joins.

1. Example: certain values, like the roles a user has in a course or the groups a user is in, are so commonly requested that they should be defined as objects that can be selected as columns.
2. Example: Course modules are often joined via module type to module tables. This should be an easy selection in the report.
3. Specific instance: Support Scales by allowing for substitution of Scale value for any integer