[docs] Add docs for storage and tensors for quantized Tensor (#51817)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/51817
Test Plan: Imported from OSS
Reviewed By: supriyar
Differential Revision: D26292464
Pulled By: jerryzh168
fbshipit-source-id: c5992deda4af949de4ea2e40edee8f22bd59b9e1
