RAAS: Build Architecture Diagram

[AymenFJA]

We will start by putting a concrete architecture of ROSE as a Service that uses RADICAL-Edge to expose endpoints.

[AymenFJA]

proposed arch. : https://docs.google.com/drawings/d/1-AgLScs16SwNROI3rsofcQU3Ci9hU7WQEJS8dygIPbk/edit