feat(secrets): updated as recommended in ashauthentication docs

lib/accounts/user.ex

@@ -32,15 +32,12 @@ defmodule Mv.Accounts.User do
 
     strategies do
       oidc :rauthy do
-        client_id "mv"
-        base_url "http://localhost:8080/auth/v1"
-        redirect_uri "http://localhost:4000/auth/user/rauthy/callback"
+        client_id Mv.Secrets
+        base_url Mv.Secrets
+        redirect_uri Mv.Secrets
+        client_secret Mv.Secrets
         auth_method :client_secret_jwt
         code_verifier true
-
-        client_secret fn _, _ ->
-          Application.fetch_env(:mv, :oicd_client_secret)
-        end
       end
 
       password :password do