Copy types from DefinitelyTyped into index.d.ts

[richardbarrell-calvium]

Summary

• Add in the TypeScript types from DefinitelyTyped.
• (But omit the ARTStatic type because the documentation for @types/react-native-community/art doesn't mention a default export anywhere, and change the name 'ARTText' to just 'Text' to match the exports.)
• Fix issue #12

Test Plan

Clone and run a test project which uses TypeScript and ART:

• git clone https://github.com/richardbarrell-calvium/ReactNativeArtTypescriptTest.git
• cd ReactNativeArtTypescriptTest
• yarn
• (cd ios; pod install)
• react-native run-ios
• react-native run-android

Verify that tsc passes:

• yarn tsc

Introduce a type error and verify that tsc no longer passes:

• Edit App.tsx, replace strokeWidth={2} with strokeWidth="2"
• yarn tsc
• Verify that it fails with a type error like "Type 'string' is not assignable to type 'number | undefined"

What's required for testing (prerequisites)?

• node
• yarn
• Xcode
• Android SDK

What are the steps to reproduce (after prerequisites)?

• Create a new project with react-native and typescript
• yarn add @react-native-community/art
• Add a line import {Surface} from '@react-native-community/art' to a typescript source file
• yarn tsc
• TypeScript prints an unhappy message about there not being any types for the art module.

Compatibility

OS	Implemented
iOS	✅
Android	✅

Checklist

• [X] I have tested this on a device and a simulator
• [ ] I added the documentation in README.md - skipped because taking advantage of the TS types is transparent
• [X] I updated the typed files (TS and Flow)
• [ ] I added a sample use of the API in the example project (example/App.js) - skipped because the example project does not use TypeScript

[richardbarrell-calvium]

@Esemesek thank you! ♥️