Rename methods and variables in Layouts to fit new DOM free behavior

We are on our way to decouple the layouts from measuring inside of the DOM and instead calculating everything using `yoga`. Once all layouts are finally transitioned, we should rename some functions and variables in the layouts to fit the new behavior, such as the ones that contain `viaDOM` in their name. We discussed this briefly in https://github.com/LivelyKernel/lively.next/pull/1432.