Quality check coordinates

The erroneous coordinates in #345 and #343 indicate that we need to be more careful with the station coordinates when adding new stations.

I suggest that we attempt to do some QC of the coordinates. This could be, for example check that the coordinates of the stations are indeed within the specified country of the station.

@IoannisSifnaios, @kandersolar Any other ideas for enhanced quality control of new/existing stations' coordinates?

Start by reviewing the erroneous-coordinate issues #345 and #343, then read the station data and existing validation entry points in the repository. The issue suggests checking whether station coordinates fall within the station's specified country, but the desired checks and completion criteria still need agreement in the comment thread.

Written by the indexing model from the issue text.