Improvements to the component and API

• IntersectionObserve now requires a reference to the node it's observing, means the component only deals with observing and not polluted with Class or Style.

Now the component's context includes a reference which needs to be provided with the element that needs to be observed.

@using Blazor.IntersectionObserver

<IntersectionObserve>
    <div @ref="context.Ref.Current">
        Hey... I'm @(context.IsIntersecting ? "in view": "out of view")
    </div>
</IntersectionObserve>

• A new dispose method on the service rather than disconnect. Disconnect follows the API and removes any elements that are being observed but does not remove the observer.
• Remove underlying shared observer, instead each IntersectionObserve instance will have their own observer.
• Updates to documentation to reflect the above changes.
• Include a minified script file for js import.
• Bump outdated npm packages.