feat: use hasql-pool-0.10, add db-pool-max-idletime (#2786)

- new option db-pool-max-idletime limits the maximal idle time of a
  postgresql connection, defaults to 30 seconds
- this essentially restores the db-pool-timeout option from versions
  <=10, with more specific name

src/PostgREST/CLI.hs

@@ -154,6 +154,9 @@ exampleConfigFile =
       |## Time in seconds after which to recycle pool connections
       |# db-pool-max-lifetime = 1800
       |
+      |## Time in seconds after which to recycle unused pool connections
+      |# db-pool-max-idletime = 30
+      |
       |## Stored proc to exec immediately after auth
       |# db-pre-request = "stored_proc_name"
       |