Add the ability to specify a profile on the CLI

[sesh]

Some (most?) of us have access to multiple AWS accounts from the command line. It would be super-handy to be able to specify which profile to use with the --profile CLI argument like you can with awscli.

[depado]

A workaround while waiting for this feature :

Store your credentials in your project (and don't version it of course) and change the AWS_CONFIG_FILE environment variable to point to that file before executing chalice. I didn't test it yet but that should do the trick.

[garnaat]

You should be able to just set AWS_PROFILE environment variable to pick the desired profile from your standard config file. But I agree having a --profile option makes sense.

[MartijnHarmenzon]

I noticed this is possible on deployments also, which is great. But can it also be done on local like:
chalice local --profile my-profile-name