Refactor Vulkan context into its own files. Use RAII. (#42273)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/42273
Test Plan: Imported from OSS
Reviewed By: IvanKobzarev
Differential Revision: D23252335
Pulled By: AshkanAliabadi
fbshipit-source-id: 43144446f2f3530e6cb2a85706a9afc60771347d
