Updating 7 wuschel maps

updated: RA map POSEIDON - facelift, small tactical changes on middle
island.
updated: RA map PLUTO - corrected oil derrick that was not capturable.
updated: RA map ARTEMIS - some cosmetic changes on main island.
updated: RA map ARES - minor yaml changes to MISS.
updated: RA map APOLLO - minor yaml changes to MISS.
updated: RA map DIONYSUS - cosmetic changes on main island, minor yaml
changes to MISS.
added: RA map ZEUS, 256x320 (lo and behold, the father of all mapz!)

Note: ZEUS, ARTEMIS and APOLLO need
https://github.com/OpenRA/OpenRA/pull/3375 to be implemented in order to
avoid lags. The first map is lagging badly.