Remove "PHID Manager" Tool list interface

Summary: This was well-intentioned but has not actually proven to be useful.

Test Plan:

• No list tab shows up anymore.
• Looked up a PHID.

Reviewers: btrahan, jungejason, Girish

Reviewed By: Girish

CC: aran, jungejason, edward, emiraga, Girish, nh, tuomaspelkonen, epriestley

Maniphest Tasks: T631

Differential Revision: 1234