Ender3 BLTouch Mount with Captive Screws

BLTouch Mount for the Ender3 with the following features:
* Semi-captive screws - the two mounting holes have extended "tubes" that taper towards the hole. Screws will insert easily, and when you remove them they can't fall. This takes away a major annoyance with installing/removing this holder.
* Fits the Ender3 stock carriage.

Note Sept-12-2023: I've switched from using this on my printer to a new version that also replaces the fan holder, located here: https://www.thingiverse.com/thing:6214140 - I'd definitely recommend that design over this, although this one is fine and served me well for years.