Put deprecation warnings undre Pleroma.Config.

lib/pleroma/application.ex

@@ -22,7 +22,7 @@ def user_agent() do
   def start(_type, _args) do
     import Cachex.Spec
 
-    Pleroma.DeprecationWarnings.warn()
+    Pleroma.Config.DeprecationWarnings.warn()
 
     # Define workers and child supervisors to be supervised
     children =

lib/pleroma/config/deprecation_warnings.ex

@@ -2,7 +2,7 @@
 # Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
 # SPDX-License-Identifier: AGPL-3.0-only
 
-defmodule Pleroma.DeprecationWarnings do
+defmodule Pleroma.Config.DeprecationWarnings do
   require Logger
 
   def check_frontend_config_mechanism() do