Improve layout of schedule for screen readers

[kburk1997]

I am currently testing the schedule page with ChromeVox, and it is very confusing from just a screen reader. Suggestions:

• Add link to skip to schedule before earliest time on schedule (each time is read out)
• Add screen reader only info for each class stating time and start and end date. Bootstrap 4 has the sr-only class to facilitate this.

Otherwise, everything is in the correct order.