strace: Disable bluetooth support by default

strace: Disable bluetooth support by default

The bluetooth support adds a bluez5 dependency (and,recursively, a lot
of other stuff). Disable it by default to avoid having to build all of
this when it is not needed.

This decrease the number of tasks run for a core-image-minimal build by
~1000 (-21%).

To re-enable bluetooth support in strace, add "bluez" to strace
PACKAGECONFIG. For example, in local.conf:
  PACKAGECONFIG:append:pn-strace = " bluez"

Fixes [YOCTO #15323]

[RP: Tweaked to put a message about the change in the recipe]
Signed-off-by: Yoann Congal <yoann.congal@smile.fr>
Suggested-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>