feat: notion OAuth setup (#11765)

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

app/controllers/notion/callbacks_controller.rb

@@ -0,0 +1,36 @@
+class Notion::CallbacksController < OauthCallbackController
+  include NotionConcern
+
+  private
+
+  def provider_name
+    'notion'
+  end
+
+  def oauth_client
+    notion_client
+  end
+
+  def handle_response
+    hook = account.hooks.new(
+      access_token: parsed_body['access_token'],
+      status: 'enabled',
+      app_id: 'notion',
+      settings: {
+        token_type: parsed_body['token_type'],
+        workspace_name: parsed_body['workspace_name'],
+        workspace_id: parsed_body['workspace_id'],
+        workspace_icon: parsed_body['workspace_icon'],
+        bot_id: parsed_body['bot_id'],
+        owner: parsed_body['owner']
+      }
+    )
+
+    hook.save!
+    redirect_to notion_redirect_uri
+  end
+
+  def notion_redirect_uri
+    "#{ENV.fetch('FRONTEND_URL', nil)}/app/accounts/#{account.id}/settings/integrations/notion"
+  end
+end