(utils) Send node names, topic names and anyother string from launch file

[ShikherVerma]

The code of nodes should not have string constants in them. For example if I change the name of forwardServer from "forward" to something else then everything will stop working. Better would be to give these strings to node from the launch file so that we can see all such strings in one place. also we can use xmacro ros pkg to simplify our ros launch files.