Display time taken for CPD

[matt-goldman]

From @ncn-ssw:

There is nowhere that the time taken for professional events is displayed. With this feature, the app could be used to record Continuing Professional Development (CPD) hours for professionals registered with Engineers Australia and Australian Computer Society. I believe this would be a very attractive feature for those professionals.

cc: @adamcogan @AntPolkanov @lukecookssw @camillars
This is a great suggestion from Nick - should we consider adding this to the roadmap? I think this extends beyond the Rewards app and is applicable to SSW events in general.