Add template events in posting_topic_review & mcp_topic

Events:

• posting_topic_review.html
  • posting_topic_review_row_post_details_before
  • posting_topic_review_row_post_details_after
• mcp_topic.html
  • mcp_topic_postrow_post_details_before
  • mcp_topic_postrow_post_details_after

The events will allow adding content before and after the post details in topic review and topic moderation. Similar events are already present in viewtopic_body.html: https://github.com/phpbb/phpbb/blob/release-3.1.9/phpBB/styles/prosilver/template/viewtopic_body.html#L264-L266

The events will be used in my Post Numbers extension to display the post numbers.