Switch credentials from Zemke-Rhyme to Vault

Summary:
Credentials have been migrated to Vault.

Ref T1425
Ref T930

Test Plan: Test on Dwellers

Reviewers: DorianWinty, dereckson

Reviewed By: DorianWinty, dereckson

Maniphest Tasks: T1425, T930

Differential Revision: https://devcentral.nasqueron.org/D2800