Proposal: Add aws load balancer timeout override to service template

As AWS still seems to be the most popular k8s cluster provider for installing Workflow, seemingly even for dev clusters, perhaps the annotation mentioned in https://deis.com/docs/workflow/managing-workflow/configuring-load-balancers/#idle-connection-timeouts should be added to the default router service [template](https://github.com/deis/router/blob/master/charts/router/templates/router-service.yaml) so that operators don't bump into issues stemming from the default load balancer timeout of 60s, as seems to be the frequent case currently.

Thoughts?