Performance enhancement for first turn AI settling

Modding:
- Added UnitAction unique type for modder clarity and ruleset validation
- Converted "May enhance a religion" , "May found a religion" uniques to UnitAction

Golden age points decrease with negative happiness  - By Framonti

City-States don't trigger defensive pacts  - By tuvus

By SomeTroglodyte:
- City overview top bar fix
- Fixed crashes in Android for unit art in civilopedia

Fixed free building errors - By SeventhM