Implement `LvRegionCoordinator`

[sebastian-peter]

Implement an actor that cuts the osm data at administrative boundaries of a given level. The data is then recursively divided into smaller pieces, until the level of municipalities is reached. From there, data is handed over to MunicipalityCoordinator.

• Implement messages, understood by the actor
• Implement logic, reacting on messages
• Determine data and configuration needs and eventually compile another issues from that
• Write tests