Allow inline comment in attachments as it was allowed in Confluence Server

In Cloud the only way to comment on attachments/files like PDFs is via the "/attachments" macro.

In server, it was possible to do this without having to use the "/attachments" macro.

• The current process to insert an inline comment within Confluence Cloud can be confusing and hidden for most users. Previously within the server version, you could click on an attached PDF on the page and produce an inline comment. If you click on the attachment now, there's no indication that on how to perform an inline comment. It just appears to be gone. This makes the user assume that the feature is gone completely.
• Once a user does figure out that they need to use the attachment macro, it's still unclear on how to do it. You must expand the attachment macro and finally click view. Compared to the server version, this is obscure and not well explained.
• The current way of adding the attachment macro takes up a large portion of the page. This takes away from the cleanliness of the page. We don't want a giant plugin taking up half the page just to use inline comments within a PDF.