Another consistency pass, part 1

Yet another :lipstick: pass to get our code samples using uniform variable names and example values, not overuse `{placeHolders}`, trim unnecessary repeated comments, and things like that.

- [x] autoscale. This section does need more work; there's a bunch of unnecessary `{groupId}` placeholders that should be replaced with some form of `groupObject.getId()` calls, and there are places where half of the samples update metadata while the other half don't, that sort of thing. I'm not familiar enough with autoscale to touch them up myself, though. :cry: 
- [x] cloud-block-storage
- [x] cloud-databases
- [x] cloud-dns
- [x] cloud-files
- [x] cloud-images