Extract core functionality from mesh module into a new module

See merge request walberla/walberla!271

Refactor pystencil integration

See merge request walberla/walberla!273

This new function does the actual generation using pystencils and creates a target library that can be used as a dependency as usual. One should not list the python script itself anymore in add_executable.
Convention: Use the AppName as a prefix for the generated lib!

Example Usage:

waLBerla_generate_target_from_python( NAME AppNameGeneratedLib FILE GenerateKernel.py OUT_FILES Kernel.h Kernel.cpp)

waLBerla_add_executable ( NAME AppNameGeneratedLibTest DEPENDS GeneratedLib)

Update references in documentation

See merge request walberla/walberla!269

Combined resolved/unresolved coupling methods showcase

See merge request walberla/walberla!264

since std::vector<bool> behaves differently to std::vector using bool
can cause troubles

Adapted paramater references in Split template

See merge request walberla/walberla!268

pystencils: Boundary generation for non-LB fields and for inner_or_boundary=False

Closes #111

See merge request walberla/walberla!266

pystencils_walberla: use type-safe getData instead of uncheckedFastGetData

Closes #110

See merge request walberla/walberla!261

pystencils: re-allow use of arbitrary field names in sweeps

See merge request walberla/walberla!267

Silence CMake FFTW3_MPI warning

See merge request walberla/walberla!265

Previously, anything that wasn’t velocity, src, src_tmp, pdfs, pdfs_tmp resulted in invalid code

This was a regression introduced in a1614152

Fixes for MESA-PD: Shape type duplication checks and mass/inertia on some shapes

See merge request walberla/walberla!263

[API] merge integrators with/without shape

See merge request walberla/walberla!262

To remove code duplication the distinction is now moved
into the generator. Default kernels are "with shape".

flattened shallow copy of field

See merge request walberla/walberla!258

add open merge requests from pystencils_walberla

See merge request walberla/walberla!260

Add codegen into CI

See merge request walberla/walberla!259