Toggle the use of use imperativeHandle

[dutchcelt]

The goal is to allow users to create wrappers with a specific behavior for useRef by toggling the application of 'useImperativeHandle'.

This PR does three things:

1. Adds the config option withImperativeHandle
2. Using the option to omit the useImperativeHandle feature so that users can retrieve the custom element from ref.current.
3. The useImperativeHandle when used, now gets a 'customElement' property as a fallback to retrieve the custom element.

[break-stuff]

I think this can be simplified. By updating the ref prop on the custom element like this:

      ref: (node) => {
        ref.current = node; // Assign the DOM node to the internal ref
        if (typeof forwardedRef === "function") {
          forwardedRef(node); // Support callback refs
        } else if (forwardedRef) {
          forwardedRef.current = node; // Support object refs
        }
      },

That should resolve the ref mapping issue and we should be able to remove the useImperativeHandle function completly.

[dutchcelt]

I can update the commit removing the useImperativeHandle and related methods and using the simplified ref function. Unless you'd rather do that?

[break-stuff]

Please, go ahead. You've done most of the leg work already. 😄

[break-stuff]

@dutchcelt The fix has been deployed under v1.7.1. I appreciate your help on this!