initial, mindless conversion

This PR is a simple conversion of all Controller closures to methods.

I've not undertaken refactoring explicit references to params to method args.  In some cases there isn't symmetry between the RESTful API and the model, so there is code like this

```
        String policyName = params.id ?: params.policy
          UserContext userContext = UserContext.of(request)
          ScalingPolicy policy = awsAutoScalingService.getScalingPolicy(userContext, policyName)
```

Rather than guessing about style preferences, I've kept this PR simple.