refactor: remove usage of Control.Debounce

This change replaces usage of Control.Debounce in Logger with makeDebouncer function extracted from AppState to a new module PostgREST.Debounce.

src/PostgREST/Debounce.hs

@@ -0,0 +1,19 @@
+module PostgREST.Debounce
+  ( makeDebouncer) where
+
+import Protolude
+
+-- | Make a new debouncer action. An internal "worker" thread runs forever
+-- ensuring "action" runs when the "trigger" is called. The "action" is only
+-- executed once over a burst of calls.
+makeDebouncer :: IO () -> IO (IO ())
+makeDebouncer action = do
+  flag <- newEmptyMVar
+
+  let worker = forever $ do
+        takeMVar flag
+        action
+      trigger = void $ tryPutMVar flag ()
+
+  void $ forkIO worker
+  pure trigger