migrate usb device detection

Move the usb device detection logic that's a patch in entity manager to
pcie_bifurcation to keep all bifurcation related code in a common place.

Based on
- https://gbmc.googlesource.com/meta-gbmc-staging/+/e1bac3c2109b9f79449616e3c5da0b06a6974932/recipes-phosphor/configuration/entity-manager/0005-Add-USB-Device-discovery-daemon.patch

Google-Bug-Id: 281642829
Change-Id: I79af52f715914bd494e360d30ae241cb4d104014
Signed-off-by: Willy Tu <wltu@google.com>