Customizable grommet

**Latest model (with minor enhancements) is available over at MakerWorld** https://makerworld.com/en/models/516545

Customizable grommet. Useful when you need to make a hole in a solid surface (e.g. wall, desk) for running cables through, but want it to look nicer than a bare hole and don't want other stuff (bugs, weather, crumbs, etc) getting through.

The customizer allows splitting the grommet STL in half (along length or width) to make it easier to print (eliminates supports) and easier to plug the hole (if you want a flange on both sides). Default cut is "hotdog" style which is the easiest for inserting into a hole in drywall. "Hamburger" cut may be better if you can cap two sides of a hole separately.

By default the second end will mirror whatever customizer settings you use for the first end, but that can be overridden if you need an asymmetrical grommet.

You can use scissors/clippers/knife/whatever to make additional cuts in the flaps to make it easier to run cable