add source code to footer, remove unneeded layouts

lib/layouts/post_layout.ex

@@ -5,19 +5,6 @@ defmodule MonoTab.PostLayout do
   def template(assigns) do
     ~H"""
     {{:safe, render(@inner_content)}}
-    <%= if @page[:date] do %>
-      <time datetime={@page[:date]}>{format_date(@page[:date])}</time>
-    <% end %>
     """
   end
-
-  defp format_date(date_string) when is_binary(date_string) do
-    case Date.from_iso8601(date_string) do
-      {:ok, date} -> Calendar.strftime(date, "%B %d, %Y")
-      {:error, _} -> date_string
-    end
-  end
-
-  defp format_date(%Date{} = date), do: Calendar.strftime(date, "%B %d, %Y")
-  defp format_date(_), do: ""
 end