Figure out how to address asynchronous lectures/sections

This application was built before COVID, and back then most lectures and sections had meeting times and places. Now with COVID, what used to be an "edge case" is now like half of the cases lol.

Some things to consider:

• Assume that a lecture may be async while its classSections are not, and vis-a-versa.
• The Schedule entity needs to be updated to store the asynchronous lectures/sections
  • If a course doesn't have a meeting time, the user can use any enroll code. So in cases like the UI we should probably show all the enroll codes.
  • Sections are typically synchronous, and they do have enrollment limits
• The frontend should be updated with a popover to show the async events
  • Need to update both the grid and list views