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/race.sql

@@ -0,0 +1,14 @@
+WITH race_names AS (
+	SELECT "index" AS id, "text" AS name FROM text_data WHERE category = 33
+)
+SELECT
+	race.id,
+	race_names.name,
+	race.grade,
+	race.thumbnail_id,
+	MIN(race.id) OVER (PARTITION BY race_names.name) AS "primary",
+	ROW_NUMBER() OVER (PARTITION BY race_names.name ORDER BY race.id) - 1 AS "alternate"
+FROM race
+	JOIN race_names ON race.id = race_names.id
+WHERE race."group" = 1
+ORDER BY race.id