Import/Export Sections

Sometimes it is easier to create smaller map to make up the entire map you want as the memory needed can get quite large so it would be great to be able to merge different builds into one larger one. And just as much if you create a huge map foundry sometimes does not like it as the memory is too large so maybe if you create a large map the ability to split the map into sections and export all sections to different images or .json files would be amazing.