useShadowDom documentation updates

[mfulton26]

1. the d.ts file uses optOutFromShadowRoot but the js code uses useShadowDom which means the type name is inverted

   react-web-component/index.d.ts

   Line 2 in 4b02a84

   export const create: (app: JSX.Element, tagName: string, optOutFromShadowRoot?: boolean) => void;

2. the example in the readme is inverted (should be false but is true)

   react-web-component/README.md

   Line 54 in 4b02a84

   ReactWebComponent.create(<App />, 'my-component', true);

3. it might make more sense to pass in an options object to create instead of a single boolean flag so that it is clearer what true or false is doing at the callpoint

   e.g.

   ReactWebComponent.create(<App />, 'my-component', {useShadowDom: false});

   instead of

   ReactWebComponent.create(<App />, 'my-component', false);