Use functions from standard library

[suzumiyasmith]

Problem: Those two functions exist in de facto library

purescript-oak/src/Oak/Document.purs

Line 17 in fd70885

appendChildNode :: Element -> Array Node -> Effect Unit

purescript-oak/src/Oak/Document.purs

Line 20 in fd70885

getElementById :: String -> Effect Element

Solution: Import from standard library

https://pursuit.purescript.org/packages/purescript-web-dom/4.0.0/docs/Web.DOM.Node#v:appendChild

https://pursuit.purescript.org/packages/purescript-web-dom/4.0.0/docs/Web.DOM.NonElementParentNode#v:getElementById

Example Usage:

https://github.com/purescript-concur/purescript-concur-react/blob/720879aba03c0cdfaad0d813d7b0fb5f32e8d614/src/Concur/React/Run.purs#L16-L16

Additional context
❤oak