Core: blog field for categories

## Ready State: Yes

This pull request is related to the following JIRA tickets: https://imagex.atlassian.net/browse/LDC-203
Also PR https://github.com/imagex/imagex_blog/pull/8

## Requirements & Dependencies

* This new module requires imagex_blog_categories submodule, features, uuid, uuid features

## Deployment Instructions

* Merge code.

## Usage/Test Instructions

* ensure blog content type now has a blog categories field.