Get standard out from cloudwatch

[arokem]

Currently, viewing the standard out of any given machine on Batch can (only?) be done by logging into the AWS console, clicking through to cloudwatch and finding the relevant job. Would be nice to be able to pull down that log and print it to stdout on the user's machine for debugging of failures and similar.

[richford]

And / Or (at the very least) provide a link to the relevant cloudwatch log so that the user doesn't have to navigate there by themselves.

[richford]

Each BatchJob object has a log_urls method, implemented here in 73fa8aea. I started implementing the option to print to standard out but I think I would prefer to leave it as is and just supply the CloudWatch link(s).

Arguments for:

• URL version is already implemented
• Print to stdout version is tricky to implement since for long logs, the events will be paginated
• Hopefully, linking to the AWS console teaches the user a bit more about the AWS ecosystem

Arguments against:

• User has to leave the python console.
• User may have to login to AWS providing an additional barrier

What do you think @arokem?