Allocate external Rocm allocator via PyBind (#7148)
* Enabled rocm support for graph transformations
* Support for external Hip allocator
* Added const_cast to reinterpret_cast to fix compiler issue
* Another crack at fixing the compile error
* More compilation fixes
* Added compilation flags to load_inline extension
* Added ROCM, ROCM_PINNED constants
* Changes to address PR comments
* Changed gpu identifier from ROCM to CUDA
* Added HIP compilation flag for torch inline functions
* Fixed a typo in header allocator string formatting
* Fix for runtime error with external_cuda_allocator
* Removed cuda/rocm specific code paths for allocators
* More name changes to generic gpu from rocm/cuda
* Removed duplicate allocator creation
* Rename cuda_external_ config options as gpu_external_
* Rename hip_mem_limit to gpu_mem_limit
* Rename cuda_mem_limit to gpu_mem_limit
