workstation: pulseaudio USE -bluetooth

To support the third party pulseaudio-modules-bt package containing hifi
codecs.

profiles/role/workstation/package.use

@@ -4,6 +4,9 @@ media-libs/libsdl2 gles2
 # Required by www-client/firefox[system-libvpx]
 media-libs/libvpx postproc
 
+# For pulseaudio-modules-bt
+media-sound/pulseaudio -bluetooth
+
 # For virt-manager
 net-dns/dnsmasq script
 net-misc/spice-gtk usbredir