Add capability to export FE functions for visualisation using the ADIOS2 library
This MR extends the dataexport capabilities of HyTeG by allowing to use the ADIOS 2: The Adaptable Input Output (I/O) System version 2 to write FE function data to file for visualisation with ParaView.
The corrent implementation so far only supports functions of type
- P1Function + P1VectorFunction
- P2Function + P2VectorFunction
- P2P1TaylorHoodFunction
but is easily extensible by adding another specialised sub-writer class.