Restructure data handling work flow. Current workflow should be splitted into

• Station Preparation (#140 (closed))
• Data Preparation (#141 (closed))
• Data Collection (#142 (closed))
• Iterator (#143 (closed))

Specific requirements are listed in related issues. In general the advanced data handling should help to create inputs from different data sources (neighbouring stations, model fields, etc).

Use lukas_issue135 as root to create any branches related to this milestone.