[FluentKeyCode] Allow content to avoid using the Anchor property

[dvoituron]

[FluentKeyCode] Allow content to avoid using the Anchor property

Adding a ChildContent property and a ´ElementReference` to apply the KeyCode engine to the FluentKeyCode content.

If the ChildContent is filled, the Anchor attribute is no longer used (and is ignored).
A new GlobalDocument property defines the component as global to the page, using the DOM object document.

Example:

<FluentKeyCode OnKeyDown="@KeyDownHandler">
   Hello World
</FluentKeyCode>

The HTML result will be:

<span>Hello World</span>

Breaking changes

No

Unit Tests

Updated