Configure asynchronous settings

@stealthycoin

I would like to be able to configure my pure lambda function's asynchronous settings straight from my chalice config.json file.

In particular, I want to be able to set the retry attempts and the maximum age of events in the config.

Start by examining how pure Lambda functions are represented and configured through config.json. Trace the existing asynchronous Lambda configuration path, then verify that retry attempts and maximum event age can be set there and are applied to deployments; use the project’s relevant configuration tests if available.

Written by the indexing model from the issue text.