Clear diplomatic modifiers and countdowns to resurrected civs

Puppeted cities remove "marked for improvement by building" markers correctly

Modding:
- Specific uniques for gold purchase cost always override default cost
- Global uniques can accept unit trigger conditions when placed on units

By unciv-loof:
- Border expansion logic 
   - considers neighboring bonus resources at the edge of work range
   - does not consider unexplored tiles  
   - slightly prioritizes contested tiles