Make upcoming events view more viewer-oriented

Summary:
Ref T11326. Try to make this a little more useful:

• Don't show entire attendee list (not useful?)
• Show host (useful?)
• Show your own status prominently (attending vs declined vs invited).
• Show cancelled events prominently.

Test Plan:

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T11326

Differential Revision: https://secure.phabricator.com/D16299