Community parts

It's important for Mozilla engineering to understand which parts of this project are critical to Gecko, and which parts are there for external users (such as wgpu-rs applications).

Here is the list of logic parts that are not needed by Gecko:

• separation of wgpu-types from wgpu-core
• wgpu-rs
• everything around surfaces, swap chains, and presentation
• buffer mapping
• multi-threading support
• native-only extensions