Fix remaining code `TODO` comments

A few TODO statements are in the codebase:

nrm/applications.py
    49  not a real model

nrm/controller.py
   123  better choice

nrm/coolr/clr_nodeinfo.py
   102  not sure this is unique [xxx]

nrm/coolr/clr_rapl.py
   203  fix the total energy tracking later [xxx]

nrm/powerpolicy.py
    62  Need to set this value when DVFS policies are added
    81  Need to add a better policy selection logic in addition to user
        specified using manifest file
   124  Add DVFS and Combined policies

Edited May 14, 2019 by Valentin Reis