Replace Arraytypes with xtensor in Proxy interface

.gitlab-ci.common.yml

.gitmodules

CMakeLists.txt

external/aocommon

idg-api/BufferSet.cpp

idg-api/BufferSetImpl.h

idg-api/BulkDegridder.cpp

idg-api/DegridderBuffer.cpp

idg-api/GridderBuffer.cpp

idg-bin/CMakeLists.txt

idg-bin/examples/cxx/common/common.h

idg-bin/examples/cxx/distributed/common/common.h

idg-bin/examples/cxx/plan/main.cpp

idg-bin/tests/cxx/CPU/Reference/main.cpp

idg-bin/tests/cxx/CUDA/wtiling/backward.cpp

idg-bin/tests/cxx/CUDA/wtiling/forward.cpp

idg-bin/tests/cxx/common/common.cpp

idg-lib/src/CPU/common/CPU.cpp

idg-lib/src/CPU/common/CPU.h

idg-lib/src/CUDA/Generic/Generic.cpp