Add Enrolment Audit to UIs Survey workbook

[Brian Lewis]

this will import a data table, and build a pivot table from this that can be configured to look like any of the sheets A2, A3, A5 A6.

Also provide an end point

api/warehouse/enrol/isced/<year>

to get this audit as JSON or a standalone workbook.

[Brian Lewis]

feat(uis survey): add audit for enrolment numbers

Resolves #1129

→ <<cset e787f6150882>>