Implement Intersection Observer

[meesrutten]

Because we are currently using the scroll event to track the vertical position of components. I figured the Intersection Observer may seem more fitting for this purpose.
The Intersection Observer is perfect for these purposes:

• Image lazy loading
• Infinite scroll
• Launching actions based on viewport visibility

Since it handles component positioning asynchronously it may boost performance quite a bit :)

[riccoarntz]

definitely worth looking into, need to test how accurate it is and wether it covers all of our current functionalities such as providing a threshold per component.