Add enhancements when exporting for data frames for longitudinal/repeating projects

[pwildenhain]

For longitudinal projects

• [ ] If there are no events mapped to instruments, then don't include redcap_event_name

For repeating projects/instruments

• [ ] Add a project level attribute (is_repeating, has_repeating, etc)
• [ ] Include in the index automatically

for projects with both

• [ ] include redcap_event_name, redcap_repeat_instrument, redcap_repeat_instance?
• [ ] test with a CGT data ops project