Merge branch 'fhennig/lambdas' into 'v2.0-dev'

.gitlab-ci.yml

conftest.py

docs/source/api/codegen.md

docs/source/backend/gpu_codegen.md

docs/source/backend/index.rst

docs/source/backend/platforms.md

docs/source/backend/platforms.rst

docs/source/contributing/index.md

docs/source/installation.md

docs/source/user_manual/gpu_kernels.md

pytest.ini

src/pystencils/backend/memory.py

src/pystencils/backend/platforms/cuda.py

src/pystencils/backend/platforms/generic_gpu.py

src/pystencils/backend/platforms/platform.py

src/pystencils/backend/platforms/sycl.py

src/pystencils/codegen/__init__.py

src/pystencils/codegen/config.py

src/pystencils/codegen/driver.py

src/pystencils/codegen/errors.py