extract config files

src/config/carpool.config.ts

@@ -0,0 +1,19 @@
+import { registerAs } from '@nestjs/config';
+
+export default registerAs('carpool', () => ({
+  departureTimeMargin: process.env.DEPARTURE_TIME_MARGIN
+    ? parseInt(process.env.DEPARTURE_TIME_MARGIN, 10)
+    : 900,
+  role: process.env.ROLE ?? 'passenger',
+  seatsProposed: process.env.SEATS_PROPOSED
+    ? parseInt(process.env.SEATS_PROPOSED, 10)
+    : 3,
+  seatsRequested: process.env.SEATS_REQUESTED
+    ? parseInt(process.env.SEATS_REQUESTED, 10)
+    : 1,
+  strictFrequency: process.env.STRICT_FREQUENCY
+    ? process.env.STRICT_FREQUENCY === 'false'
+      ? false
+      : true
+    : false,
+}));