(RT 4863) Prune accounts from vanadium's manifest

vanadium's role has long ago shifted from being a sandbox for ad-hoc data
analysis work to being a puppetized piece of infrastructure, but the access
control list has not been updated to reflect this change. This patch limits
access to vanadium to roots. I and Andrew Otto retain sudo: I manage the
EventLogging stuff on the server, and Otto is responsible for issues relating
to integration with the analytics cluster.

This change also drops the MySQL class from vanadium's manifest. It was there
as a temporary measure while I was waiting for the EventLogging db on db1047 to
be set up. It has been since set up, so this class is no longer required.

Change-Id: Ie976c230b483e5bab471b6723238c618f731330f
Merge "(RT 4863) Prune accounts from vanadium's manifest" into production