Dates in email template do not grab from settings

[pierreTklein]

Describe the bug
Admins can update the app open / close times / confirm times from the website, but the emails we send to hackers don't capture that data.

We should update the handlebar emails so that they have date templates, and then pass in the stuff from the settings when generating the email.

To Reproduce
Receive any email from the API

Expected behavior
Should have correct date in the email, which matches the open & close times in SETTINGS.