Reorganize app structure + naming

[aaron-schroeder]

• routes.py -> main/views.py
  • Also changed the name of the blueprint from 'route_blueprint' to 'main'
• Created application/utils/
  • Moved util.py there, renamed it as units.py
  • Moved converters.py there , renamed as readers.py
  • Removed calc_power() from the lost soul dashboard_activity.py and put it in a util file called dataframe.py
  • Took dashboard_activity.py around back and made sure it didn't suffer
• Renamed dash pages, dropping the dashboard_* convention
• Renamed add_dashboard_to_flask to add_dash_app_to_flask
• Changed all references to old structure and names
• Did some unused-import cleanup while I was at it; not comprehensive