util.create_lambda_function should accept a namedAny.

[alexbrasetvik]

... so the definitions are reusable, and the resulting configurations more succinct.

For instance, the example preprocessors of WebResource could be !namedAny ...web_utils.set_expires, seconds: 86400 or something.

Littering the configurations with lambdas smells bad, but using them to puzzle together tiny callables is okay. :)