Close #419 Radiation Adds HDF5 Output/Restart

This pull request:
- adds hdf5 via libspash to radiation plugin
- removes amplitude data as pure binary 
- instead adds amplitude data as HDF5
- adds correct checkpoints via HDF5
- adds automated restart
- improves seperation between communication and data write

It solves #419.

In upcomming pull requests:
- conversion factors to SI
- observer directions
- frequencies
will be stored in the HDF5 files as well
and tools for data analysis will be created. 
At this point, you require `libSplash` to use the radiation plugin.

Please ceck for that in [PluginController.hpp](https://github.com/ComputationalRadiationPhysics/picongpu/blob/f9c0a0ae9341710cddd1ab902d6a68e7152aba37/src/picongpu/include/plugins/PluginController.hpp#L36-L38) to avoid compile crashes without `libSplash`.

(*Note:* the compile suite uses "all plugins on" right now #466.)