adds_random_hex_generator_helper_function

This is so maas can use this to create ids for all its elements 
This is a little unfortunate. There's only 8 possible values per byte, so `(2**8)**3` possibilities. If you assume os.urandom is perfectly distributed (it is), there's a reasonable chance you're going to get random collisions here. That concern goes away if you pick a big enough number to replace 3. UUIDv4s have 122 bits of entropy; round up to next-largest multiple of 8 == 128 bits == 8 bytes.