I believe it's Essential Housing Tools that adds a context-menu item to your Inventory screen, "Place this item." I've found it useful for helping move items around between "storage houses" while doing large-scale redecoration or swapping of templates via SaveHouse.
What would be nice is an addon that can "Place All from Inventory" and just put all furnishings in your inventory down at / near where you're standing in a given house. This would let us use `/savehouse clear` and then go to another house and put it all back down again.
Hopefully someone with the skills to make such a thing finds it useful enough to take up! Thanks for your time.