Task/iotcore 127 documentation

Changes in the documentation to reflect information about deployment and operation and changes in the Access Control API.
What about adding a second example for illustration purposes based in the following: "if the entity belongs to the service 551 and subservices 833 and the user is "admin", then it can update entities attributes"?

In addition, I would also explain how to combine both rules (the one I refer in this comment in the "read for all" one already in the README.md), from a XACML point of view. I mean, can be the two XACML pieces installed independently ant the Access Control combines them? Or we need a single XACML integrating both?

(Probably the question is a bit newie, but many of our user could be so :)