Update event doc from wiki

Hello,

1) I have ported over part of the internal wiki

2) I did NOT include Instuctor Dashboard events until further notice. Should they be part of the event logs?

3) There are a number of discrepancies in style, language, and naming. We should go over them at an appropriate time.

The primary purpose of this initial pull request is to determine whether we are okay with the style and formatting of the table that has been chosen:
-- Do the nested tables and subtables look okay? They do not seem very nice to me, but this was the best Sphinx way to do it that I could find. We could also try to break it out more.
-- Please notice that I started using :code: to mark code fields. I can revert to make it more consistent with formatting chosen in the rest of the documentation.

Thank you.