add organizational level additional to working group and institute

[veitu]

There was feedback that it would be nice to have an additional organizational level. At the moment we have working groups that are part of an institute (e.g., working groups urban geography and geoinformatics that are part of the Institute of Geography). The idea would be to have an additional level, that you can look at emissions on working group level, institute level, but also organization level (e.g., Heidelberg University).