[BACKEND] Vulkan Runtime and SPIRV Codegen (#861)

CMakeLists.txt

HalideIR

Makefile

include/tvm/ir_pass.h

include/tvm/runtime/c_runtime_api.h

python/tvm/__init__.py

python/tvm/_ffi/runtime_ctypes.py

python/tvm/contrib/spirv.py

python/tvm/ndarray.py

python/tvm/target.py

src/codegen/codegen_c.cc

src/codegen/codegen_common.h

src/codegen/llvm/codegen_llvm.cc

src/codegen/spirv/build_vulkan.cc

src/codegen/spirv/codegen_spirv.cc

src/codegen/spirv/codegen_spirv.h

src/codegen/spirv/intrin_rule_spirv.cc

src/codegen/spirv/ir_builder.cc

src/codegen/spirv/ir_builder.h

src/pass/rewrite_unsafe_select.cc