Add summaries field to Activity post
While discussing #549 (closed) we decided to add summary field to activity posts see #549 (comment 33884)
On the backend:
- add summary field to Activity post, it should support markdown
On frontend:
- Admin part:
- add html editor for summary field before content field
- Public part:
- replace article content with summary on the entry page (TBD if no summary, then maybe show content?)
- on the article display page summary should go to HTML meta TBD