Mark blog articles as specific to Version 1.0 or Version 2.0

[placer14]

Let's include some frontmatter to the jekyll template which allows a tag to indicate which version of OpenBazaar this article is specific to. Something like about_ob_release: 1 or similar.

The template could switch on the integer to apply whatever styling we'd like as the versions roll out. If a post is about ver 2, we tag with appropriate frontmatter and when we deprecate it we now have something to conditionally add content similar to the following:

NOTE: The following content is meant to be used with OpenBazaar version XX which is no longer actively maintained. A current article may be found at http://PreloadedSearchForAlreadyEmbeddedTagsAssociatedWithThisArticle.

Idea came from reading this article was out of date and needs to be updated with the above note. This would make adding these notes much easier as we find filter through our blog's old content.