Update the loader documentation in the following ways:
 1. Move documentation to new "docs" folder"
 2. Split LoaderAndLayerInterface.md into multiple docs to focus
    on target audience:
      - Top-Level     LoaderInterfaceArchitecture.md
      - Applications  LoaderApplicationInterface.md
      - Layers        LoaderLayerInterface.md
      - ICDs          LoaderImplementationInterface.md
 3. Upload newer images and their corresponding original Inkscape files.
 4. Cleanup and update sections on Linux directory search
 5. Add new sections to detail items missing
      - VkConfig
      - Handling undef Fuchsia
 6. Language cleanup

Thanks to @charles-lunarg and @smcv for feedback and various section language
corrections.