Add Ability to Publish AWS AMIs to Multiple Regions

[joelmccoy]

Currently we only publish AMIs to us-west-2 for commercial and us-gov-west-1 for govcloud. We should support publishing to other regions outside this. Packer has a built in mechanism to copy the AMI to mulltiple regions via ami_regions. However, we will need to refactor our e2e tests and publishing to account for this.

We can add in other regions as a parameter here but we will need to refactor and consider:

• Adding additional regions to that publish step may increase the publish time? (unless this happens in the background, need to confirm)
• The e2e test is run after this publish step and then cleans up the AMI if the e2e test fails. We need to refactor the cleanup task to cleanup AMIs in all the regions that it has been published to

A possible workflow might be:

1. Publish AMI to all regions at once (may take add additional time unless the copying happens in the background?)
2. Run e2e tests with published AMI
3. If fails, cleanup all images that have been copied into all the regions (requires modification of the cleanup script)