Add ability to insert posts into middle of queue and automatically push other posts by one slot

User feedback:

A related topic is the ability to insert a post into the middle of a queue, and push all the later posts back one slot.

User goal: I currently have weekly posts queued for several months, but want to make a time-relevant post this week. I want to insert something to the start of the queue and push everything back. My workaround would be to deschedule the first post, then add it to the end - but this is cumbersome because of the above issue (can't use "schedule next slot"), so I need to scroll for several months down).