PETSIRD basic C++ example

This directory provides a skeleton for C++ example code to read/write PETSIRD data. You need to yardl generate in the model directory first.

Check the example in the PRDdefinition repo first.

Compile the code:
```
cd cpp
mkdir -p build && cd build`
cmake -G Ninja -S .. -DHDF5_ROOT=$CONDA_PREFIX
ninja`
```
If you did not use conda to install HDF5, do not add the -DHDF5_ROOT=$CONDA_PREFIX part of the cmake line.