Re-enable automated notification of applications that have reached an accept/reject criteria

[brittag]

We have an old email template at https://github.com/doubleunion/arooo/blob/master/app/views/applications_mailer/votes_threshold.html.haml for notifying the membership coordinator that an application has reached criteria for acceptance/rejection.

We commented this out when we switched to membership application rounds (where we accepted/rejected all applications in a big batch at the end of the round, instead of one by one).

We're switching back to a rolling process, so the voting coordinator should get notified, so they can take action. So we should re-enable this, but make it email the voting coordinator instead of the membership coordinator.

See Routine application cycle.

[brittag]

We decided to wait on this one for now & see if the future new voting coordinator wants it to be enabled.