Fix AWSRecognizer.create()

[JamesBrill]

Why

The means of creating a specification-compliant Speech Recognition class from this polyfill (AWSRecognizer.create()) is currently broken. To integrate this polyfill with libraries like react-speech-recognition and other consumers that need such a class to work with, this needs to be fixed.

What

• Install the fantastic Speech Recognition types from Definitely Typed that are strangely absent from the main TypeScript dom library
• Use these types to fix some type errors and make it possible to painlessly type the create class factory
• Fix the create class factory to return a class that has a constructor with no args and that instantiates an AWSRecognizer with a given config
• Add the create class factory to the native speech recognition class so that it works on browsers that support it natively
• Boy Scout: fix some type errors related to Error objects (based on standard practice recommended by Kent C Dodds)

[ceuk]

Merged. I've added you as a collaborator as well @JamesBrill - I've just not got the time lately to give this enough attention