add event times to scheduled events page #3176

### Summary
Added the time for event activities to the scheduled events page, alongside the participant. 

##### Actions
*  Added `activity_time` as one of the factors that gets parsed out of the `scheduled_activities_report` and made available to the view
* Added two helper methods, one to sort the activities by their activity_time for display, and another to convert the string 24-hour format time to AM/PM format time.
* Implemented the helper methods in the scheduled activities tab of the `welcome#index view`.
* Minor tweak to the CSS for time display