README incorrect/inconsistent

[chris-bosman]

Actual behavior

If using the configuration set in the README, Shredder will fail to start.

Expected Behavior

Configuration as described in README to work.

Steps to reproduce

Try to get Shredder to work with the described configuration

Issue 1:
It's not made explicit that the operator will need to manually create the SNS topic. This should be made clear.

Issue 2:
reference.conf uses the SNS topic name spinnaker-lifecycle-pending, while the README indicates spinnaker-shutdown-pending. The lifecycle hook, whether it be manually created or done via Spinnaker, will fail due to this name mismatch.

Issue 3:
IAM permissions for the EC2 instances are incomplete and, in some cases, incorrect. Firstly, when attempting to run Shredder, the instance was unable to identify its autoscaling group due to missing the permissions autoscaling:DescribeAutoScalingInstances and autoscaling:DescribeLifecycleHooks.

Secondly, Shredder was unable to create the necessary SQS resources because the formatting of the Resource in the instance IAM permissions is incorrect. Instead of arn:aws:sqs:*:<account_id>:*:*, it should be arn:aws:sqs:*:<account_id>:*.

Thirdly, Shredder throws a warning when attempting to leverage the RecordLifecycleActionHeartbeat or CompleteLifecycleAction permissions because it wants the Resource to be formatted as arn:aws:autoscaling:*:*:autoScalingGroup:* instead of arn:aws:autoscaling:*:*:*.

Issue 4:
The provided 2.1.0 release debian did not seem to work out of the box, and attempting to create it via gradlew required manual modifications of ./shredder-ec2/build.gradle, specifically the archStr needed to be changed from noarch to all to successfullly build the debian.