all: generate json, not code

This includes modifying horsebot to use the generated JSON, as well as
moving the generator to another cmd/ directory.

Remove the generated code while we're here.
Koka tests still have to be updated, but it requires a JSON parser.

cmd/horsegen/sql/spark-effect.sql

@@ -0,0 +1,9 @@
+SELECT
+	factor_group_id,
+	effect_id,
+	target_type,
+	value_1,
+	value_2
+FROM succession_factor_effect
+WHERE factor_group_id NOT IN (40001) -- exclude Carnival Bonus
+ORDER BY factor_group_id, effect_id, id