top10: 1.3.0 - Refined input JSON to match the new general stats-format

* Adapted the configuration to the changed type-mapping for the key.
* Refined the class `Key`, that defines the JSON for the input key.
** Added attribute `type` with value of type `enum StatsType`.
** Renamed attribute `user` to `channel`.
** Renamed attribute `word` to `key`.
* Refined the class `Entry`, that defines the JSON for the input value.
** Renamed attribute `word` to `key`.
* Adapted test-classes and -cases accordingly.