Tools: scripts: copy param_parse.py JSON output as part of build_parameters.sh

This will populate https://autotest.ardupilot.org/Parameters/ArduCopter/
with the json output

Tools/scripts/build_parameters.sh

@@ -28,6 +28,13 @@ generate_parameters() {
     if [ -e "ParametersLatex.rst" ]; then
     /bin/cp ParametersLatex.rst "$VEHICLE_PARAMS_DIR/"
     fi
+    F="apm.pdef.json"
+    if [ -e "$F" ]; then
+	    /bin/cp "$F" "$VEHICLE_PARAMS_DIR/"
+        pushd "$VEHICLE_PARAMS_DIR"
+          xz -e <"$F" >"$F.xz.new" && mv "$F.xz.new" "$F.xz"
+        popd
+    fi
 }
 
 generate_sitl_parameters() {