add: config to emit warning for legacy target names

Adds the `url_use_legacy_target_names` config.

Enabled (default):
* It allows using the resource name in filters,
  orders or limits when it has an alias, e.g.
  `table?select=alias:target(*)&target.id=eq.1`
* Logs a WARNING with a hint to use the alias
* Returns a Warning header in the response

Disabled:
* It returns an error, only the alias is allowed
* No warnings returned

This feature is deprecated

test/io/configs/no-defaults-env.yaml

@@ -41,6 +41,7 @@ PGRST_SERVER_TRACE_HEADER: X-Request-Id
 PGRST_SERVER_TIMING_ENABLED: true
 PGRST_SERVER_UNIX_SOCKET: /tmp/pgrst_io_test.sock
 PGRST_SERVER_UNIX_SOCKET_MODE: 777
+PGRST_URL_USE_LEGACY_TARGET_NAMES: false
 PGRST_ADMIN_SERVER_HOST: 127.0.0.1
 PGRST_ADMIN_SERVER_PORT: 3001
 PGRST_ADMIN_SERVER_UNIX_SOCKET: /tmp/admin_io_test.sock