(GUI editor) App Editor visual update
After discussing in #1316 the best course of action is to render the app instead of the abstract view. This will require some research in how to render the app in parts, as well as workarounds for data reliant blocks, empty pages and other constraints.
The goal is a view that is close to the app preview but does not allow you to interact with the blocks content. Blocks are shown with a bounding box and highlighted on hover. non-visual blocks have a dashed boundary On click the property menu opens and the block is selected. Drag and dropping a block changes their position in the app-definition.yaml.