floss: Add hcidoc tool to read snoop files

Hcidoc will be used to analyze snoop files and snooz files to identify
errors and other behaviors. This commit simply sets up the hcidoc crate
and a simple snoop reader.

Bug: 262928525
Tag: #floss
Test: ./build.py --target utils
Change-Id: I7eeae136a35d51a01ac2ab137dbf114e07f800e9