Add application-level power profiling support

Need to add application-level power profiling support to allow NRM to report application run power/energy profiles. This is required to assess the effectiveness and impact of power policies currently in NRM and that will be added in the future.

A possible solution is to use SensorManager measure the initial and final values. The difference in values can be reported as a part of the application 'exit' event.

Note: This is a very basic solution and does not handle multiple containers/applications. Will have to fix this in the future.

Tasks involved:

• Add an option to manifest file to enable profiling
• Make changes in SensorManager to allow ​calculation of the difference in measured (stored) values using rapl_reader functions
• Make changes in NRM to display profiling information at the end of an ​application run