Sweden: Skolverket schools layer not reliable

[matthiasfeist]

Hi.

I just wanted to discuss an issue with the layer sources/europe/se/Skolverket-schools.geojson that has been added by @magol in PR #1672. I'm planning a manual import effort and therefore did a little research on this dataset. We found that the geodata quality is relatively bad. I even was in contact with Skolverket and discussed the issue with them. They know that their spacial data is bad, but they'll not correct it (see here)

I therefore suggest to remove this layer from the index. I didn't want to open a PR to remove it before discussing it though :)