Remove old, unused code.
Merge branch 'feature/generic-datum' of github.com:SolarNetwork/solarnetwork-sites into feature/generic-datum

* 'feature/generic-datum' of github.com:SolarNetwork/solarnetwork-sites:
  Add helpers for display scales.
  Add locationUrlHelper class, and update the endpoint helper functions to work with both nodeUrlHelper and locationUrlHelper to load common data sets (available range, sources, and datum list).