JS API to access DOM elements by ID via delegated properties

[jonnyzzz]

See KT-32552 for more details.

Provides a short access to document elements by ID via delegated
property syntax. Received element is not cached and received
directly from the [Document] by calling [Document.getElementById]
function on every property access. Throws an exception if element
is not found or has different type
To access an element with theId ID use the following property declaration

val theID by document.gettingElementById

To access an element of specific type, just add it to the property declaration

val theID : HTMLImageElement by document.gettingElementById

[jonnyzzz]

I've moved the PR to the kotlinx.html repository. Please fill free to close it