Task executions should be named

[James Santucci]

Task execution IDs are not super helpful. It's conceivable that someone will have distinct runs of a task that have meaningful names, e.g. for a hello world task "hello to james" or "hello to aaron". This is information that's easy for users to use to search, but we don't support it right now.

We should support names on task executions and also allow filtering by name

This partially blocks #368