yunbridge: add linux side python code

to make the bridge work we need to run an askfirst instance on the ttyS.
additionally add the lua scripts needed to make REST work. this is really ugly
code but it works. i already cleaned up to the original code, but there are still
issues such as a new luci session being created for each request.

Signed-off-by: John Crispin <blogic@openwrt.org>

utils/yunbridge/files/etc/config/yunbridge

@@ -0,0 +1,6 @@
+config bridge config
+	option socket_timeout 5
+	option secure_rest_api false
+
+	# remove this line to activae the yunbridge
+	option disabled	1