COMMENTS: Use the same attachment/comment functionality for projects

[nickbe]

With this feature comes also the following:

1. When creating a ticket then use the current upload option, but create a new comment from these attachments instead of attaching the uploads directly to the issue.
2. Entereing a text should not be needed if the comment contains at least one attachment. It should then be displayed differently (the redesign takes this into account)
3. Allow adding attachments to comments later if I'm a manager OR if I created the revelant issue.