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/observability/ObsHelper.hs

@@ -122,6 +122,7 @@ baseCfg = let secret = encodeUtf8 "reallyreallyreallyreallyverysafe" in
   , configInternalSCQuerySleepFst   = Nothing
   , configInternalSCQuerySleepSnd   = Nothing
   , configServerTimingEnabled       = True
+  , configUrlUseLegacyTargetNames   = True
   }
 
 testCfg :: AppConfig