arrow

ARROW-17579: [Python] PYARROW_CXXFLAGS ignored? (#14074)

This PR adds:
- `PYARROW_CXXFLAGS` variable to PyArrow C++ and Pyarrow cmake builds (both defined in `setup.py`)
- a common flags section to `pyarrow/src/CMakeLists.txt` where `CXX_COMMON_FLAGS` and `PYARROW_CXXFLAGS` are added to the `CMAKE_CXX_FLAGS` variable.

Other flags defined in Arrow C++ should be included in PyArrow C++ and PyArrow with `include(SetupCxxFlags)`.

I am not sure if additional flags that are defined in PyArrow, see: https://github.com/apache/arrow/blob/43670af02f0913580fd20e26006fd550d6fdf2da/python/CMakeLists.txt#L134-L174 are needed in PyArrow C++ as they were not used when PyArrow C++ was included in Arrow C++?
cc @pitrou 

Authored-by: Alenka Frim <frim.alenka@gmail.com>
Signed-off-by: Alenka Frim <frim.alenka@gmail.com>