Updates to Course Screen UI

Includes:
- Updating filter choice names
- Remove "See Activity" button
- Adding slight styling to filter dropdown
- Changing heading based on filter selection
- Updating assignment feedback for students
- Updating button/text logic to account for overlapping answer/compare periods
- Adding blank state text for the filter
Merge branch 'develop' of github.com:ubc/acj-versus into develop

 Please enter a commit message to explain why this merge is necessary,