chore(): start moving some packages to the core directory (#7215)

packages/cli/create-medusa-app/src/utils/postgres-client.ts

@@ -0,0 +1,17 @@
+import pg from "pg"
+const { Client } = pg
+
+type PostgresConnection = {
+  user?: string
+  password?: string
+  connectionString?: string
+  database?: string
+}
+
+export default async (connect: PostgresConnection) => {
+  const client = new Client(connect)
+
+  await client.connect()
+
+  return client
+}