[FEATURE] Add a data source field to Events BB

[sandeep-ps]

Is your feature request related to a problem? Please describe.
Currently, we don't have an easy way to figure out the source of event data. It would be good to add a data source field to capture this.

Describe the solution you'd like
Add an optional text property dataSource to the Event schema with enum values "Web Tools", "Events Manager", "Campus Rec Fusion", "Illinois App", and "Other".

Describe alternatives you've considered
An alternative solution will be to have no enums and keep this a free-flowing text field. The downside is that client applications could enter any value that they choose.

Additional context
None.