feat: notion OAuth setup (#11765)

Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>

config/routes.rb

@@ -228,6 +228,10 @@ Rails.application.routes.draw do
             resource :authorization, only: [:create]
           end
 
+          namespace :notion do
+            resource :authorization, only: [:create]
+          end
+
           resources :webhooks, only: [:index, :create, :update, :destroy]
           namespace :integrations do
             resources :apps, only: [:index, :show]
@@ -265,6 +269,11 @@ Rails.application.routes.draw do
                 get :linked_issues
               end
             end
+            resource :notion, controller: 'notion', only: [] do
+              collection do
+                delete :destroy
+              end
+            end
           end
           resources :working_hours, only: [:update]
 
@@ -493,6 +502,7 @@ Rails.application.routes.draw do
   get 'microsoft/callback', to: 'microsoft/callbacks#show'
   get 'google/callback', to: 'google/callbacks#show'
   get 'instagram/callback', to: 'instagram/callbacks#show'
+  get 'notion/callback', to: 'notion/callbacks#show'
   # ----------------------------------------------------------------------
   # Routes for external service verifications
   get '.well-known/assetlinks.json' => 'android_app#assetlinks'