Fix course search filtering by term, level, and gereq

[drewvolz]

Closes #6765

Fixes incorrect results when filtering by term, level, and ge requirements

• Adds helper methods for filtering by the above criteria
• Adds more performant large list props to course search results list

[codecov[bot]]

Codecov Report

Merging #7084 (0851c68) into master (7296c40) will decrease coverage by 0.09%. Report is 9 commits behind head on master. The diff coverage is 0.00%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #7084 +/- ## ========================================= - Coverage 8.48% 8.39% -0.09% ========================================= Files 304 304 Lines 5117 5169 +52 Branches 1373 1395 +22 ========================================= Hits 434 434 - Misses 4655 4707 +52 Partials 28 28 ```