Just got back from Versailles. Here's the current status of what is happening there: It is A-OK to take food and water in plastic/metal bottles into the palace and other site there. And at least in the palace and in the gardens, when going through the security checkpoint you don't even have to pack away your water bottle. You can be openly carrying it in your hand. And I recommend you do carry water because it gets really hot, and there aren't water fountains. Many, many people were carrying water.
We went through multiple security checkpoints (because each area has it's own bag inspection, where they run it through an x-ray machine or visually inspect the inside of your bag). And for sure when they did their visual inspections, our food and water was clearly visible, and they did not comment on it.
In fact, going into the palace, they noticed our metal butter knife (for cutting bread and spreading cheese) in one of our backpacks during the x-ray scan at the security checkpoint. They asked to see it. We opened up the backpack and pulled out our food bag an opened it up in front of them to take out the knife. They didn't comment or object to the food. And after seeing that the knife was a butter knife, they let us proceed with it.
By the way, we took this same bag with food and the butter knife into every major site in Paris that we visited (including all three star sites in the Rick Steves book) without any objection--with the exception of the Marmotten-Monet Museum which required people to leave their water bottles on shelves at the entrance, but were OK with the food.)
Also, at Versailles, I'm sure they had luggage storage somewhere, but I was looking for it and didn't see any signage alerting us to it. Most people had packs of some sort they were carrying. (I expect they want to keep the luggage storage for people who have bigger packs or suitcases and really need it.)