First major refactoring

Initially, I wanted to separate the "engine" from the data.

Today I did the first step in this direction. Pull request #92

Now posts are stored not as React components but as a serializable tree.

This refactoring will allow not only to separate the "engine" from the data but also to separate the templates into a separate package. That means that sooner or later, there will be more than one theme :)

And the data itself can now be stored anywhere, which means that there will be connectors to MongoDB, Postgres, or JSON files.

It means that today is the birthday of the Bar part of barhamon.com :)