Add dropdown components, menus for RS auth items

app/components/dropdown_link_component.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+class DropdownLinkComponent < ViewComponent::Base
+  def initialize(href:, separator: false, add_class: nil)
+    @href = href
+    @class = class_str(separator, add_class)
+  end
+
+  private
+
+  def class_str(separator, add_class)
+    str = "no-underline block px-4 py-2 text-sm text-gray-900 bg-white
+           hover:bg-gray-100 focus:bg-gray-100 whitespace-no-wrap"
+    str = "#{str} border-t" if separator
+    str = "#{str} #{add_class}" if add_class
+    str
+  end
+end