Allow Anchors to use 'target' rather than 'targetComponentIdentifier'

[dustinleblanc]

Apple supports both of these target types for anchors: https://developer.apple.com/documentation/apple_news/anchor

Allowing for setting anchors using just plain IDs instead of a component means that you can anchor items to specific paragraphs in a body field rather than anchoring to the body field itself (I am doing this within the context of a Drupal 8 site).

I imagine this would just be adding a setTarget to the Anchor class.