Make payment method management somewhat more reasonable in Phortune

Summary: Ref T2787. Shows somewhat-useful information, allows payment methods to be disabled and renamed.

Test Plan: Created, renamed, disabled payment methods.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T2787

Differential Revision: https://secure.phabricator.com/D10203