Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Add PSM and Load Factor SDP parameters to the BNEP based profiles
(NAP, GN and PANU). No reason to not to support them.

Separate SDP parameters data structures for the BNEP based profiles.

Generalize Service Availability SDP parameter creation.

Requested by: Iain Hibbert < plunky at rya-online dot net >
MFC after: 3 days

Import sdpd(8) sources. This is Bluetooth Service Discovery Protocol daemon.
Extend libsdp(3) API to allow service registration and removal.
Fix uninitialized variable bug in sdpcontrol(8).

Reviewed by: imp (mentor)
No objection: ru