32650 Battery holder/ guide

This is a variation for those that want to make 32650 battery packs. I will add more in the future. Since I needed it done first, the 4P version (4 cell) is the closest to being complete. I plan to cover 2P-8P. This design has built in spacing to keep the nickel strips isolated so they don't make contact with anything unintentional. The spacing of the cells themselves was decided on for ample cooling while still being capable of fitting within reasonable space requirements.