Add license headers

[MartinPontius]

Needed at least for the packages WeatherRoutingTool and maridatadownloader

[iquaresma]

license header added in ImproveDocumentation

[EHJ-52n]

Did you add the license header using a tool (for java you can use maven to generate and update the license headers, e.g. license-maven-plugin) or manually? Maybe something similar exists for python...