Fix increased costs on some truepath buildings

[Kelenius]

I noticed that garden of eden's cost in the wiki is much lower than in-game. Investigating it, I found that some truepath buildings are missing path: ['truepath'] that prevents cost increase in truthAdjust. These buildings are:

• Garden of Eden facility
• Tau Ceti basic housing
• Tau Ceti pylons
• Tau Ceti casino

I've added the missing tag to these buildings. There are also isolation-specific templated buildings (captive housing, horseshoes, nanite factory, assembly, and event-specific stuff), but it missing there is probably intentional.