Breaking: Add configuration error note for single view plugins


To prevent the usage of plugins that should only be used on post views we are now adding additional checks for those. If no post could be resolved - also means if the plugin is used on pages that do not match the Constants::DOKTYPE_BLOG_POST - the plugins will now return a new message to make the miss usage visible.

` A possible configuration error was detected. No matching post could be obtained. Make sure that this plugin is only used on a post. `

The following plugins will now show this message if no post could be obtained:

  • Authors
  • Footer
  • Header
  • Metadata
  • RelatedPosts

Templates added:

  • Layouts/Post.html

Templates changed:

  • Templates/Comment/Comments.html
  • Templates/Comment/Form.html
  • Templates/Post/Authors.html
  • Templates/Post/Footer.html
  • Templates/Post/Header.html
  • Templates/Post/Metadata.html
  • Templates/Post/RelatedPosts.html