Support hybrid In situ/In transit pipelines // Refactor tests and examples

This MR introduces a way to handle hybrid In transit/ In situ pipelines using AdiosCatalyst. AdiosCatalyst can execute an In-Situ Paraview Catalyst pipeline before sending the data through ADIOS2. This allows the simulation to perform a synchronous data reduction before sending the data over the network to the visualization node, performing a visualization asynchronously. A detailed example and 2 test (no MPI/MPI) have been created.

In addition, this MR completely refactors the testing and examples architecture of the project; instead of having separate but identical executables for tests and examples, we now just have a single one.

Depends on paraview!6568 (merged)