Add generic method for header

Unify Header to be able to use it from the admin as from the seg_management.

app/components/concerns/header.rb

@@ -0,0 +1,23 @@
+module Header
+  extend ActiveSupport::Concern
+
+  def header(&block)
+    provide(:title) do
+      "#{t("#{namespace}.header.title")} - #{title}"
+    end
+
+    tag.header do
+      if block_given?
+        tag.h2(title) + capture(&block)
+      else
+        tag.h2(title)
+      end
+    end
+  end
+
+  private
+
+    def namespace
+      controller_path.split("/").first
+    end
+end