Change config key from EDX_TIM to EDX_ORA2

Hide course staff debug info in studio preview

Show item_id (location) in Course Staff Debug section.

It's cumbersome to get otherwise, and staff will want it for state
resetting (if it comes to that).

Add event and INFO level logging.

This introduces a few features:
* INFO level logging on common events like creating or fetching
  submissions and assessments.
* Parallel event logging for the same.
* Creates a local logs/ directory for development.

For the most part, we rely on XBlock's publish() mechanism to emit
event data. However, because scoring is done at the API layer in a way
that is not directly visible to the OpenAssesmentBlock, we're logging
that event separately with a hacky solution that dynamically loads an
emit function based on a configuration value. This is a stopgap
measure until we can start using the edX analytics API (which is still
in testing).

TIM-260, TIM-378

Course staff can see counts

Change scenario due date to be in the future and minor changes to prompt text.

Revert setup.py name change back to ora2

Preserve line breaks in prompt

Fix 500 error when self-assessment has default dates

Add UI styling for course staff, including collapse/expand.
Cache student item when retrieving submission and student item.
Protect against invalid cache key exceptions.
Update test suite to clear cache between tests.
Add composite index for AssessmentWorkflow student item fields

Changing is_open to is_closed. We're negative like that.

UI Clean Up - Small Tweaks

Performance changes for staggered deadlines

This change improves the query when you have 35,000 open peer workflows and 0 assessments. Performance appears to still be good for a fluid workflow as well.

TIM-337: Feedback on assessment UI

Adding start date validation to assessment modules

Sylvia/ora2/tim 384

Acknowledge Submission Deadline