Consider to use C++ implementation in Python runtime

[mikir]

Because optimization of pure Python performance has its limitation (see #466), consider to go futher and try to use C++ implementation for some Python runtime classes.

The class BitStreamReader is a good example. Ideally, usage C++ implementation should be completely transparent for users. If zserio pypi package contains pre-compiled C++ binaries of runtime classes for current platform, they will be used automatically to speed up Python performance. If not, pure Python implementation will be used. However, it will be good if users will be able to force usage of pure Python implementation.

[Mi-La]

Measurements with binding of C++ BitStreamReader and BitStreamWriter:

See #466 comments for introduction to the measurements.

Currently measuring with the following command (READ,WRITE,READ_WRITE):

scripts/test_perf.sh python python-cpp -d test/language/parameterized_types/zs -s parameterized_types.zs \
        -f build/test/python/language/parameterized_types/packed_array_element_param_1000.blob \
        -b parameterized_types.packed_array_element_param.Database -n 5 -c READ

• Python 3.8.16

Performance Tests Results - READ
========================================================================
| Generator            | Total Duration | Iterations |   Step Duration |
|----------------------------------------------------------------------|
| Python               |     3133.034ms |          5 |       626.607ms |
| Python (C++)         |     1831.597ms |          5 |       366.319ms |
========================================================================
Performance Tests Results - WRITE
========================================================================
| Generator            | Total Duration | Iterations |   Step Duration |
|----------------------------------------------------------------------|
| Python               |     5061.803ms |          5 |      1012.361ms |
| Python (C++)         |     3475.836ms |          5 |       695.167ms |
========================================================================
Performance Tests Results - READ_WRITE
========================================================================
| Generator            | Total Duration | Iterations |   Step Duration |
|----------------------------------------------------------------------|
| Python               |     8395.415ms |          5 |      1679.083ms |
| Python (C++)         |     5430.077ms |          5 |      1086.015ms |
========================================================================