DOCUMENTARY PREMIERE: Part 1 of 2. This four-hour documentary, concluding tomorrow night on ABC, comes not from the network’s news division, but as a co-production by People magazine and Four M Studios (the recently rebranded TV production arm of Time Inc.). So, essentially, it’s People, so expect that level of depth, which isn’t much. But ABC might as well devote four hours of valuable prime-time real estate to a look at Britain’s Royal Family – because really, thi