backend hanwatts prediction model web interface

Merge pull request #26 in UPRFIR/backend-hanwatts-prediction-model-web-interface from UPRFIR-202-backend-weather-route-aanpassen-aan-sd to develop

* commit '80ea30234b211dedc37489fec00d417360e9343a':
  Deleted unused imports, updated routes & controller try/except
  ongebruikte import verwijderd
  removed flask-abort import
  Created exceptions for different error handling.