Added sd-bus service example

Added obmc-phosphor-example-sdbus.
Added sdbus-service class for common logic.
diff --git a/meta-phosphor/common/recipes-phosphor/obmc-phosphor-example-sdbus/files/org.openbmc.examples.SDBusService0.conf b/meta-phosphor/common/recipes-phosphor/obmc-phosphor-example-sdbus/files/org.openbmc.examples.SDBusService0.conf
new file mode 100644
index 0000000..45af4f4
--- /dev/null
+++ b/meta-phosphor/common/recipes-phosphor/obmc-phosphor-example-sdbus/files/org.openbmc.examples.SDBusService0.conf
@@ -0,0 +1,8 @@
+<!DOCTYPE busconfig PUBLIC "-//freedesktop//DTD D-BUS Bus Configuration 1.0//EN"
+ "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
+<busconfig>
+  <policy user="root">
+    <allow own="org.openbmc.examples.SDBusService0"/>
+    <allow send_destination="org.openbmc.examples.SDBusService0"/>
+  </policy>
+</busconfig>