Add back support for the use of HubL tags inside of the blog content module

Previously sites used to be able to use HubL tags of any kind in a blog post.

Commonly to add additional data to blog posts we would use text and rich text tags in the blog post detail template.

That is no longer possible without using some hacks. This makes storing additional details and displaying them a real pain in the butt.

More obnoxious is the fact we can't use `{% module %}` or `{% custom_widget %}` in the blog post detail.

We developed a custom module that has a special sharing widget to it. We now can't use this module because there's no way to embed it without using javascript to move it after the page load to the right place, and we don't want to do that.

I am about ready to completely stop using the blog content module all together because of these problems. It used to work great, now it's become really restrictive.

I don't honestly know how I'm going to handle the post content anymore because scrapping that module creates a worse editing experience for marketers as they will have to edit the custom module in edit modules in order to edit the text instead.

12rVM1+

As you can see this change  has made even simple everyday things way harder in the blogs, and it negatively impacts the marketers creating and editing the blog posts because their editing experience now relies on only editing modules using the edit modules pane, no longer can they just click on the text in the page and change it.