checks: adding a static check for goimports
checks: adding a static check for goimports

This will now verify that imports are in the correct order when running 'make
static-check'. This is useful for ensuring that we are consistent with how we
order our imported dependencies.

aws/amazon-ecs-agent,kiranmeduri/amazon-ecs-agent,kiranmeduri/amazon-ecs-agent,aws/amazon-ecs-agent,kiranmeduri/amazon-ecs-agent,aws/amazon-ecs-agent,swipely/amazon-ecs-agent,swipely/amazon-ecs-agent,swipely/amazon-ecs-agent,kiranmeduri/amazon-ecs-agent,swipely/amazon-ecs-agent,aws/amazon-ecs-agent