feat: create startup file

src/startup.ts

@@ -0,0 +1,16 @@
+// Starts up applications required to run before the HTTP server is on.
+
+import { Conf } from '@/config.ts';
+import { createZapSplitsIfNotExists } from '@/utils/zap-split.ts';
+import { cron } from '@/cron.ts';
+import { startFirehose } from '@/firehose.ts';
+
+if (Conf.firehoseEnabled) {
+  startFirehose();
+}
+
+if (Conf.cronEnabled) {
+  cron();
+}
+
+await createZapSplitsIfNotExists();