Add platform-install as a subproject

Change-Id: I898b3bdd48aef56093c9ea02e5b067d57ef5fd1a
diff --git a/.gitmodules b/.gitmodules
index 41b5065..15f750f 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -7,3 +7,6 @@
 [submodule "components/cord-onos-publisher"]
 	path = components/cord-onos-publisher
 	url = ../cord-onos-publisher
+[submodule "components/platform-install"]
+	path = components/platform-install
+	url = ../platform-install