Auto-detect if the user needs react, flow, or typescript support

[saadq]

Instead of the user needing to pass --react, --typescript, or --flow flags to lynt, I could detect this automatically.

• Add React support/rules if the user has react in their package.json
• Add TypeScript support/rules if the user has a tsconfig.json file in their root project folder
• Add Flow support/rules if the user has a .flowconfig file in their root project folder