This mostly updates the bindings to the current state.
No actual logic backing them yet.

*Note*: the IDL does *not* need to be checked for matching the upstream spec precisely at this stage. The upstream is evolving, we just need to update in order to start integrating the implementation. What needs to be checked is - how C++ represents the IDL, esp with regards to derived classes, events, and hierarchies.

The trickiest points, arguably, are:
  - WebGPU -> GPU prefix change
  - the goop for interfaces that are not final

Differential Revision: https://phabricator.services.mozilla.com/D46166

--HG--
rename : dom/webgpu/InputState.cpp => dom/webgpu/DeviceLostInfo.cpp
rename : dom/webgpu/Fence.h => dom/webgpu/DeviceLostInfo.h
rename : dom/webgpu/BlendState.cpp => dom/webgpu/OutOfMemoryError.cpp
rename : dom/webgpu/LogEntry.h => dom/webgpu/OutOfMemoryError.h
rename : dom/webgpu/BindGroup.h => dom/webgpu/ProgrammablePassEncoder.cpp
rename : dom/webgpu/BlendState.cpp => dom/webgpu/RenderBundle.cpp
rename : dom/webgpu/BlendState.h => dom/webgpu/RenderBundle.h
rename : dom/webgpu/AttachmentState.cpp => dom/webgpu/ValidationError.cpp
rename : dom/webgpu/AttachmentState.h => dom/webgpu/ValidationError.h
extra : moz-landing-system : lando