Reduce turret vision & Increase Build Time

Guard Tower
- Reduced vision from 7 to 6
- Increased buildtime from 12s to 24s

Gun Turret
- Reduced vision from 7 to 6
- Increased buildtime from 15s to 30s

SAM Site
- Increased buildtime from 18s to 36s

Advanced Guard Tower
- Reduced vision from 9 to 7
- Increased buildtime from 24s to 48s

Obelisk of Light
- Reduced vision from 8 to 7
- Increased buildtime from 36s to 52s