Improve the presentation of recent activities

[dtdesign]

The list of recent activities is cramped with content, questionable semantics (username plus time inside <h3>) and too many links. It is in need of a visual overhaul that should focus on better discoverability by structuring the content and differentiating between types of content. Quoting part of a reply is fine, but simple reactions should be reduced to just the action, omitting the excerpt to reduce its visual weight.