Closes #907

Tested on Brave, Firefox and Safari (Desktop)
Test on DuckDuckGo and Safari (Mobile iOS)

Feature specs/checklist:

• User can drag blocks with the followings actions: mousedown -> mousemove -> mouseup
• When the mouse leaves the blocks container, drag does not stop
• User can still click properly on blocks to inspect them (there is no conflict between the drag and click actions)
• Disable all element selections events in the blocks container. When user move the mouse all over the page while dragging blocks, no element are selected.
• It does not break mobile interactions

Feel free to update this checklist if you see anything else.
Thank you.