FC-38 System events and handlers for blue-green deployment

Handlers for new system events have been added, but they do not have any action yet.
Also corrected an issue where rate limiter was applied for ignored messages.

Signed-off-by: Steffan Westcott <steffan.westcott@clicktravel.com>
Merge pull request #2 from clicktravel-steffan/master

FC-38 System events and handlers for blue-green deployment
FC-23 Use SQS visibility timeout of 5 minutes instead of 30 seconds

SQS queues are created such that messages have a visibility timeout of 5 minutes. This gives message handlers up to 5 minutes to process each message, instead of the default 30 seconds. Existing queues are not affected.

Signed-off-by: Steffan Westcott <steffan.westcott@clicktravel.com>
Merge pull request #3 from clicktravel-steffan/master

FC-23 Use SQS visibility timeout of 5 minutes instead of 30 seconds