[20181115134335] Drain Timeout, Resource Logs, and Bug Fixes

[ddollar]

Sends CloudFormation stack update logs for rack-level resources to convox rack logs.

Adds the ability to configure the drain timeout on Generation 2 applications through the drain: attribute on services.

• #3018 fix cli help for resources proxy [@ddollar]
• #3019 enable system volume for ecs-optimized amazon linux 2. [@ffjia]
• #3020 fall back to rack log group for stack logs [@ddollar]
• #3021 make draining timeout configurable for gen2 [@ddollar]