Convert `arc tasks` to use `PhutilConsoleTable`.

Summary: `PhutilConsoleTable` does a better job at aligning columns. We still probably need to do some work to `PhutilConsoleTable` to set a maximum width for a specified column, or elect which columns can be truncated etc but this can probably come later.

Test Plan: {F167687}

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9601