[PR] Make NTSO only available if a HoS has joined the round

[Leeanei]

If NTSO didn't exist, I'd pick secoff, yeah. If NTSO existed and secoff slots were open, I'd join NTSO because there's more sec slots open than if I'd joined as sec. HoS+NTSO+Sec=7 slots, HoS+sec = 6 slots and significantly more pressure on the HoS because on RP its uncommon for HoSes to have an IC reason to treat a HoS-off as a lieutenant.

Though, a lot of the NTSO issues being sounded out here sound more like rules/ahelpable stuff. And most of it isn't even in my experience on RP!