Show vacancy information during module registration

Problem description

The official module vacancy report provided by NUS is not real-time and not easily parsable programmatically. It is tiring to jump between NUSMods and EduRec merely to find out if some module still has a vacancy. To make things worse, there is no consistent way to query the vacancy information of a module from EduRec (select modules during rounds, appeal afterwards, and impossible to see it when one already runs out of available workload).

Possible solution

Display the vacancy information on NUSMods alongside other information during ModReg periods. Also, provide an API endpoint for that as well. As an enhancement, this might also be added as a search criterion for filtering out modules without vacancy.

Alternatives

If NUS is reluctant to grant access to its internal real-time data, it might also be possible to parse the table in vacancy report using tools such as tabula.

The issue names no repository files or tests. Start by reviewing how NUSMods obtains module data and whether EduRec access or parsing the linked vacancy-report PDF with Tabula is feasible; done means showing vacancy information during ModReg periods and exposing it through an API endpoint.