feat: use hasql-pool-0.9, add db-pool-max-lifetime (fixes #2638)

- db-pool-acquisition-timeout is no longer optional, defaults to 10s
- new option db-pool-max-lifetime limits the maximal lifetime of a
  postgresql connection, defaults to 30m

src/PostgREST/CLI.hs

@@ -151,6 +151,9 @@ exampleConfigFile =
       |## Time in seconds to wait to acquire a slot from the connection pool
       |# db-pool-acquisition-timeout = 10
       |
+      |## Time in seconds after which to recycle pool connections
+      |# db-pool-max-lifetime = 1800
+      |
       |## Stored proc to exec immediately after auth
       |# db-pre-request = "stored_proc_name"
       |