NVTX in MONAI

[drbeh]

Is your feature request related to a problem? Please describe.
Nsight Systems provide profiling of a deep learning workflow. Apart from its predefined tracking components, a user can employ NVIDIA Tool Extension (NVTX) to mark event and profile specific functions. For MONAI transforms, it is not possible to add these markers directly since it is using a compose pipeline.

Describe the solution you'd like
Wrapping NVTX functions as MONAI transformations enables profiling of any arbitrary MONAI transformation by simply adding these transformation into the MONAI pipeline.