chore: add migration for traffic data collection (#6171)

## About the changes

Adds migration for creating table `stat_traffic_usage`.
This table primary-keys on day, traffic_group, and status_code_series.
Adds individual indexes for day, traffic_group, and status_code_series.

Traffic group is the grouping for API endpoints for which traffic is
counted.
status_code_series is 200/202 etc = 200, 304 etc = 300

src/migrations/20240208123212-create-stat-traffic-usage-table.js

@@ -0,0 +1,30 @@
+
+exports.up = (db, callback) => {
+    db.runSql(
+        `
+        CREATE TABLE IF NOT EXISTS stat_traffic_usage(
+            day DATE NOT NULL,
+            traffic_group TEXT NOT NULL,
+            status_code_series INT NOT NULL,
+            count BIGINT NOT NULL DEFAULT 0,
+            PRIMARY KEY(day, traffic_group, status_code_series)
+            );
+        CREATE INDEX IF NOT EXISTS stat_traffic_usage_day_idx ON stat_traffic_usage (day);
+        CREATE INDEX IF NOT EXISTS stat_traffic_usage_traffic_group_idx ON stat_traffic_usage (traffic_group);
+        CREATE INDEX IF NOT EXISTS stat_traffic_usage_status_code_series_idx ON stat_traffic_usage (status_code_series);
+        `,
+        callback,
+    );
+};
+
+exports.down = (db, callback) => {
+    db.runSql(
+        `
+        DROP INDEX IF EXISTS stat_traffic_usage_day_idx;
+        DROP INDEX IF EXISTS stat_traffic_usage_traffic_group_idx;
+        DROP INDEX IF EXISTS stat_traffic_usage_status_code_series_idx;
+        DROP TABLE IF EXISTS stat_traffic_usage;
+        `,
+        callback,
+    );
+};