Page Layouts are superclasses

Pages inherit from a superclass that implements an `around_template`, wrapping the contents of `template` in the subclass.

# ./app/views/page_view.rb
class PageView < ApplicationComponent
  def around_template(&content)
    html do
      head do
        title { @title || "My Site" }
      end
      body(&content)
    end
  end
end