Implement nightly emailed report showing active instances, duration of uptime, launching user account

[mattlebeau-galois]

In light of the cancellation of #455 , we are asked to generate and email a report nightly with the information spelled out in the AC.

AC:

• Report should contain a list of active instances, broken down by AWS environment (excluding Production), showing: -- Accountname -- Total uptime -- Instance ID
• A report with this information is generated and distributed to a mailing distro each evening. We'll want to modify this list, but initially it can be set to mattl@galois.com, abivin@galois.com, rbroadfoot@galois.com.
• Email format: -- Subject: mm/dd/yy - account name - Active F1 Instance Report -- Reply-to: ssithgalois@galois.com -- Intro text: This email contains a report of the active F1 instances, the accountname that started them, and the total uptime per instance. It is to be used to identify any long-running instances that may have been left running mistakenly.

[mattlebeau-galois]

@rfoot - Can you please review the AC on this issue to validate that it's what you're after functionality-wise, sir? (and, of course, make any edits you see fit.)

[rfoot]

This looks great! Thanks