Interlocking rings puzzle, noob printer edition

This tweak of [emmett](https://www.thingiverse.com/emmett)'s [Interlocking Rings Puzzle](https://www.thingiverse.com/thing:813535) is intended to be easier to print by using a fully-connected first layer. While this no longer has the elegance of the print-and-go puzzle, I think that's a fair tradeoff to avoid frustration with failed prints.

The original model has several tiny pieces with a very small base layer surface area which get knocked loose easily while printing. Printing with a brim seems like overkill since most of the model doesn't need it, so this model adds a small amount of brim-style connections at the intersections to keep them in place until they get bridged to the rest of the model.

Please double-check in your slicer to make sure that the connections in the first layer are present and look reasonable. The added settings are customizable:

`brim_height`: vertical height, adjust if needed to ensure that you get one layer of brim. If it's too thin, the slicer may