Issue #40 - Add unit tests for api-tools/uploader [Finished]

[Flavore669]

Helloooo, This is the foundation for uploader testing, it's only a matter of time before I finish. In the meantime, I feel it would be beneficial if you could look over my changes in advance because why not.

Changes

• Added dependency injection pattern with connectDBFunc for testability in uploader.go
• Added test data files for courses, professors, and sections in a folder under uploader directory

Testing Approach

• Uses minimal test data to verify control flow
• Mocks database dependencies to enable unit testing

I will hopefully finish testing the Uploader function, and start testing buildStaticAggregation function soon

Please let me know if you have any suggestions or concern for testing uploader.go