Reduce the verbosity of the ./bin/search index script.

Summary: Currently, the ./bin/search index script produces a lot of output (one line for every indexed object). Instead, use a PhutilConsoleProgressBar to indicate progress. This is much less verbose and gives a real indication of how long the script should take to complete.

Test Plan: Ran ./bin/search index and verified that a progress bar was output.

Reviewers: epriestley, Blessed Reviewers

Reviewed By: epriestley, Blessed Reviewers

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9364