Rudder

Add 3 generics methods that allows users to use augeas binaries to edit configurations files on the agent.

• The first one include calling Augtool command and get a node's label value (Either by simply providing a path to the node's label as a parameter or by specifying a file associated with its lens then providing the regular path).
• The second will allows the executing of augtool commands directly on the agent.
  *The last one has the same context as the first but its purpose is to set variables.