split data in separate files

docs/systems/maintenance.md

@@ -0,0 +1,15 @@
+# Maintenance Model
+
+**Entity Type:** SystemEntity
+
+## Rules
+
+- Nearly every building has ongoing gold + workforce maintenance
+- Deleting buildings stops upkeep and frees workforce
+
+## Examples
+
+| Building | Gold/min | Workforce |
+|----------|----------|-----------|
+| Fishing Hut | -6 | 4 Tier I |
+| Bakery | -14 | 3 Tier II |