Reduced range and increased build time of static defense

As described in #4723 - this is my first attempt at a Pull Request for those changes.


Guard Tower
- Reduced range from 6 to 5
- Reduced vision from 7 to 6
- Increased buildtime from 12s to 24s

Gun Turret
- Reduced range from 6 to 5
- Reduced vision from 7 to 6
- Increased buildtime from 15s to 30s

SAM Site
- Reduced range from 10 to 7
- Increased buildtime from 18s to 36s

Advanced Guard Tower
- Reduced range from 8 to 6
- Reduced vision from 9 to 7
- Increased buildtime from 24s to 48s

Obelisk of Light
- Reduced range from 8.5 to 6.5
- Reduced vision from 8 to 7
- Increased buildtime from 36s to 52s