CONN-113: Data user

Add the data-user for message walls and forums (as on article comments)

Bug ID: CONN-113
How about using echo short tag everywhere where it's possible instead of `<?php echo ...?>`?

Also, is `$isreply` of `boolean` type? If yes, then it's a good practice to use `===` operator instead of `==`. If it's not a `boolean` then I'd think of casting it to `bool` in the controller. It should be `boolean`, right? :japanese_ogre:

Your task was only to add `data-user` attributes and if you think it'll take too much time to address all of it -- address only echo short tags, please :)