- Improved look & feel of the Grafana dashboard and the default filtering values.

- Corrected Grafana port
- Populated/Removed text placeholders
- Corrected labels in "Service" page

- updated grafana dashboard configuration

Implementing refinements in the webui: dividing forms for selecting the context and uploading json files in the home page; listing and detailing existing services.

- Each device type has a particular icon
- Icon color represents real/emulated devices
- Nodes support drag/drop
- Nodes are auto-placed in the topology
- Nodes have a tooltip showing their name/id

- Added upload of descriptors file
- Added scripts to generate descriptor files
- Arranged minor script details
- Minor bug fixing