Add enhanced analytic's using PAT to track events

Now tracks events for:
* Apply
* Enquire
* Enquire by email (direct email link)
* Expand fees
* Order prospectus
* Download prospectus

Using new event namespacing and PAT tracker.
Track course description for PG enquiries
Merge pull request #528 from unikent/feature/enhance-analytics

Add enhanced analytics using PAT