Summary:
Ref T8980. Move away from events to EngineExtensions.
This also simplifies hovercards a bit:
- Removes tasks from revision cards.
- Removes blockers/blocked from task cards.
- Removes "Send Message" from user cards.
These mostly felt cluttery to me. Open to arguments to retain them. I think we can make better use of the space, though (e.g., flags, projects + board columns).
Test Plan:
- Viewed people, task, revision, commit and project hovercards.
{F1043256}
{F1043257}
Reviewers: chad
Reviewed By: chad
Maniphest Tasks: T8980
Differential Revision: https://secure.phabricator.com/D14878
