apiserver/params: remove params.StatusData map alias

This PR removes another coupling of the `state` and `apiserver/params` package but removing the `params.StatusData` type.

The `params.StatusData` type, while not directly assignable, has the same underlying Kind as `map[string]interface{}` and has no methods was effectively an alias.

As usual, most of the code motion is in the tests, the real code is relatively unaffected.