query: 2.0.0 - Values are serialized as JSON

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works, but is very confusing

* The default-type is specified as a consumption-parameter in the command,
  that reads the input topic into the `KTable` via ``Consumed.with(..)``.
* The resulting code is confusing, because the ``Consumed``-parameter is
  used for both, the consumption of the input topic _and_ the consumption
  of stored values, if read from the state-store.
* Because of this, one might only think of the consumption of the stored
  values from the state-store, when looking at the ``Consumed.with()``-
  statement, and argue, why the type-mappings have to be specified here.