create full iteration space

src/pystencils/nbackend/exceptions.py

src/pystencils/nbackend/kernelcreation/context.py

src/pystencils/nbackend/kernelcreation/domain_kernels.py

src/pystencils/nbackend/kernelcreation/iteration_space.py

src/pystencils/nbackend/kernelcreation/options.py