Add gzip for heavy backend endpoints

[namsnath]

• Endpoints like allCourseLists and fullHeatmap return data along with a success message.
• The data is memory cached, but the whole response isn't.
• GZip can be enabled on the full response, which would lead to much lighter responses.
• This would be more efficient than enabling gzip on nginx for the response, since it would probably have to process the whole thing on every response.

Will require restructuring of the routes

• Move the logic to a function in the courseUtility file
• Add zlib for gzipping
• Keep a gzipped version of the success response
• Send the gzipped response if available
• Add a regardless parameter like in the existing queries to force an update
• Run a forced update everytime the courses are updated