Rename Controller metadata `anonymous` property

[Gudahtt]

The anonymous property of the Base Controller v2 metadata state is meant to indicate whether the state is already anonymized or not, or if it's a function, it's meant as an anonymizing function.

This property is often misinterpreted to mean the opposite of what it's intended to mean though. People have thought anonymous: true means that the data should be anonymized, rather than indicating that it has already been anonymized.

To clarify the meaning, this should be renamed to something easier to understand. Maybe anonymized?

[Gudahtt]

On second thought, it seems clearer to name this according to how we plan to use it: to add diagnostic information.

There are a few cases where we want to exclude data because it's too large, and the easiest way to do that would be with this metadata property. Seems wrong to imply it has PII just because we don't want it captured.