[PyTorch TB] Write raw tensor as tensor_proto (#104908)
This is the first diff to support logging of raw tensors for [TensorBoard Intermediate Logging](https://www.internalfb.com/intern/wiki/TensorBoard/Intermediate_Logging/)
Ultimately, we aim to support the feature where store full tensor is stored as a tensor protobuf to TB. Protobuf contains shape, dtype, and elements of the given tensor.
1. add `tensor_proto()` to `summary.py` which takes a tensor and convert to protobuf
2. add `add_tensor()` to `writer.py`
3. formatting changes introduced by `arc lint`
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Differential Revision: [D47302017](https://our.internmc.facebook.com/intern/diff/D47302017/)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/104908
Approved by: https://github.com/kunalb
