Tealight base for lithophane

I wanted something simple for a lithophane print I made, and found [ThingiJay's design](https://www.thingiverse.com/thing:4691553), but I didn't want to go through the hassle of combining the lithophane and base in Blender.

So I remade it in Tinkercad with a slot for the lithophane.
I also made the base smoother (more round, no 'edges').