Refactor Configuration API

docs/Makefile

docs/source/api/codegen.md

docs/source/api/codegen.rst

docs/source/api/jit.rst

docs/source/api/symbolic/assignments.md

docs/source/api/symbolic/field.rst

docs/source/api/symbolic/index.md

docs/source/api/symbolic/sympyextensions.rst

docs/source/api/types.rst

docs/source/contributing/index.md

docs/source/index.rst

docs/source/migration.md

docs/source/tutorials/01_tutorial_getting_started.ipynb

docs/source/user_manual/gpu_kernels.md

docs/source/user_manual/kernelcreation.md

docs/source/user_manual/symbolic_language.rst

src/pystencils/__init__.py

src/pystencils/backend/kernelcreation/iteration_space.py

src/pystencils/backend/platforms/cuda.py

src/pystencils/backend/platforms/sycl.py