Per-Day Changes, Inventory Progress

Tonight's build features a few additions; slightly updated graphics, the addition of background elements that change per day, camera snapping, and the start of an inventory system.

Per-day elements are a big addition for this game; the game takes place in the 45 minutes between getting up in the morning and going to work, but the main character lives outside of that time.  To show this, the environment changes slightly between days - on Monday there's only one dirty dish in the sink, but on Tuesday there're two.  The bed is left unmade some mornings, but nice and tidy others.  These elements are intended to add some visual variation and give the sense that this place is lived in and not a static location, and hopefully convey that time is passing as days progress - time is of the essence, after all.

I also started on the inventory system; Godot's UI is still unfamiliar to me, and I'm not having the best of luck with it - I expected my HBoxContainer (which is supposed to space elements out horizontally) would've done so as there were added here, but it did not -  instead they're all overlapping.  It's not obvious to me why that is yet, but it's tomorrow already, so I'll have to figure that out next time.