Feature: #EXTBLOG-57 - Add author relations

See https://jira.typo3.com/browse/EXTBLOG-57

See https://jira.typo3.com/browse/TE-21


Blog post can now contains one or more authors. In the frontend a box with the author profile can be rendered by a new authors plugin. It is alos possible to link to an overview of all posts by this author.


The old “author” field can still be used, but should be replaced by the new author record.

See See Deprecation: #EXTBLOG-57 - Add author relations