ReST style data access manager

During the development of the 2nd generation dashboard, the team has come up with the idea of using simple URI to specify what "resource" a dashboard widget can monitor on.

For example, if I want to display a text file in the dashboard, I can specify an URI "file://D:/tla/temp/test.txt" for loading the text file. Similarly, by using the same widget, I can use "sics://instrument/source/power" to display the current reactor power.

This URI approach is based on the ReST principle.