New data-storage

Implemented new data-storage , while still having backward compatibility ... for the moment.

The new system solely uses GSON for serialization to json format and only needs 3 classes.
Currently this PR is for reference and discussion only and is not intended for immediate approval.

There were many reasons for the change:
- Current data-framework has bugs and would need some / a lot of fixing  
  E.g. see #1119
- Using an existing serialization framework removes many possible bug-sources and ...
- ... with the reduced amount of code we have less work to do
- New framework is faster (still unconfirmed, but as we are talking about gson here, it propably is)

I tested the framework for PlayerInfo, Warp, PWarp, WeatherTimeData, Grave and Kit classes and it works perfectly and actually creates readable files, where the old system produced lot of additional garbage.