Basic support for inbound email on phabricator@c4science.ch, now it's /dev/null

Summary:

• Configure transport so phabricator@c4science.ch is forwarded to the 1st app instance
• Don't forward email for phabricator@c4science.ch on app00 to jump00 like other emails but redirect locally
• Make the email handling script on app00 work

Test Plan:

• It's annoying to test on our test instance, as we don't have MX records
• But you can receive email on a @epfl.ch email
• Create a notificaton from scitassrv18 to your email by creating a new Maniphest task
• Answer from your mail client
• Copy the source of your response from your mail client
• Copy this source to jump00
• Re-send the mail from jump00 with mail phabricator@scitassrv18.epfl.ch < /tmp/mail
• The mail is then received on app00 and processed by the php script
• It should appear on the task your created as a comment

Differential Revision: https://c4science.ch/D110