Add initial support for Intel FPGA SDK for OpenCL (AOCL) (#1474)

cmake/config.cmake

cmake/modules/OpenCL.cmake

docs/deploy/aocl_fpga.md

include/tvm/runtime/c_runtime_api.h

python/tvm/_ffi/runtime_ctypes.py

src/codegen/build_module.cc

src/codegen/codegen_aocl.cc

src/codegen/opt/build_aocl_off.cc

src/pass/verify_memory.cc

src/runtime/c_runtime_api.cc

src/runtime/opencl/aocl/aocl_common.h

src/runtime/opencl/aocl/aocl_device_api.cc

src/runtime/opencl/aocl/aocl_module.cc

src/runtime/opencl/aocl/aocl_module.h

src/runtime/opencl/opencl_module.cc

tests/python/integration/test_ewise_fpga.py