feat: add PostLayout

Author: mhanberg

priv/templates/heex/lib/layouts/post_layout.ex

@@ -0,0 +1,10 @@
+defmodule <%= @app_module %>.PostLayout do
+  use Tableau.Layout, layout: <%= @app_module %>.RootLayout
+  use Phoenix.Component
+
+  def template(assigns) do
+    ~H"""
+    <%= {:safe, render(@inner_content)} %>
+    """
+  end
+end