Improved Redox Rev.1 Case

This is a case for the [Redox ergonomic keyboard](https://github.com/mattdibi/redox-keyboard), using the PCBs from FalbaTech. There were some things about Matt's design that bothered me, so I tried to fix them here. These are the changes I made:

* Screws together from the bottom, not the top
* Mounting holes in the bottom for keyboard feet or tenting legs
* Switch holes oriented correctly for new FalbaTech PCBs
* No screw hole at the front, for better underglow appearance (still very solid and held together properly by the remaining screws)
* Alignment bars to strengthen the sides of the case and make sure it goes together properly
* Holes fit around the connectors properly **(see below)**

**This case may not fit your keyboard depending how you assembled it!** This is because of the last point above. The tolerances on the connector holes aren't very big. You will likely need to use the Fusion 360 file to modify the files for your specific keyboard. At the very least, you sho