feat: add new view and controller to display app configs together (#3563)

fixes: #3578

app/controllers/super_admin/app_configs_controller.rb

@@ -0,0 +1,21 @@
+class SuperAdmin::AppConfigsController < SuperAdmin::ApplicationController
+  def show
+    @allowed_configs = %w[FB_APP_ID FB_VERIFY_TOKEN FB_APP_SECRET]
+    # ref: https://github.com/rubocop/rubocop/issues/7767
+    # rubocop:disable Style/HashTransformValues
+    @fb_config = InstallationConfig.where(name: @allowed_configs)
+                                   .pluck(:name, :serialized_value)
+                                   .map { |name, serialized_value| [name, serialized_value['value']] }
+                                   .to_h
+    # rubocop:enable Style/HashTransformValues
+  end
+
+  def create
+    params['app_config'].each do |key, value|
+      i = InstallationConfig.where(name: key).first_or_create(value: value, locked: false)
+      i.value = value
+      i.save!
+    end
+    redirect_to super_admin_app_config_url
+  end
+end