[Task]: HTML Scalar Functions

[norberttech]

What needs to be done?

Ideally we should cover all functions from DOMParentNode

But we can start from:

• ScalarFunctionChain::querySelectorAll() - returns all
• ScalarFunctionChain::querySelector() - returns first

I don't think we need a dedicated DSL functions as those are type of functions that you execute on ref('html')

Like all other scalar functions those two would require:

• Unit tests covering edge cases
• Simple integration tests covering happy path usage on some example pipeline