Capturable husks for all mods

as this is an interesting game-play mechanic in Tiberium Wars and it also solves the problem of indestructible wrecks blocking vital cells. Tested it against bots (https://github.com/OpenRA/OpenRA/commit/1a33608b73602338663f7200c65fb12bdc2656c7 seems sufficient) and a second client on the same server (no desyncs).