Battery cluster carrier

This is an alternative to [thing:3771020](https://www.thingiverse.com/thing:3771020) that works in both TPU and PLA. It's also useful if you're paranoid and want to cover your battery terminals to make sure they don't short out when carried with other metal objects.

This has a lot of customization parameters, too many to make STLs for all the sensible possiblities, but I've created a few.

This can be built with and without pegs to attach straps. You can use TPU straps, or just a normal rubber band, or leave off the pegs entirely and use string or a rubber band around the body of the holder to keep the cups on the batteries. (The included straps don't work in PLA, sorry.)

The pair of TPU caps with attached single strap (pictured, center) works OK for TPU and tight tolerance on a 1x4 set of batteries, but it probably woudln't work well on larger sets. Four attachable straps is probably overkill for a small pack, but probably would help a lot with larger packs.