Rewrite `source.polygon` into array of outers without holes (closes #5264, closes #5250, closes #5272)
Rewrite `source.polygon` into array of outers without holes
(closes #5264, closes #5250, closes #5272)

openstreetmap/iD,digidem/iD,kartta-labs/iD,digidem/iD,ngageoint/hootenanny-ui,AndreasHae/iD,morray/iD,kartta-labs/iD,kartta-labs/iD,morray/iD,AndreasHae/iD,ngageoint/hootenanny-ui,ngageoint/hootenanny-ui,openstreetmap/iD,AndreasHae/iD,openstreetmap/iD