Set osmosis_replication_base_url

[pnorman]

OSM PBFs have the properties osmosis_replication_base_url and osmosis_replication_sequence_number. Even if we can't set the latter until #6 is figured out, the former should be set to https://planet.openstreetmap.org/replication/minute

[zerebubuth]

I can see the benefit of this, but why choose the minute replication? Someone might want to update the planet with hourly or daily diffs. If we're not providing a sequence number, then I feel like providing the base URL is simply confusing.