Combine Regions for research#235

Would be great to combine different regions for keyword research. For instance - we have clients, that are only active in a couple of states in Germany. Combining those would be a great time saver.

Other reason could be to only select states close to the sea or to the alps, or doing different research for eastern or western Germany.

Simple solution: combine existing regions to larger custom regions (could also combine a country with states close to a border.

More advanced: instead of adding up, it could also allow to select a larger region and deselect part of it. Think Germany without Bavaria … instead of combining the 15 other states.

Thanks!