Allow embedding multimedia content located on remote servers

Re: CSP-8387

Currently, when embedding multimedia content on Confluence you are restricted to embedding files located on the Confluence server. The page http://confluence.atlassian.com/display/CONF20/Embedding+Multimedia+Content singles out "security reasons" as the reason for this limitation.

In a secure/trusted environment (e.g. corporate intranet) it would be very good if this restriction could be removed or relaxed through an administrative option.

Why is this a good idea?

Media files are usually very large. Storing large files as Confluence attachments is not always such a good idea. We don't need them version controlled (not to the granularity that Confluence provides) and we don't want them stored in the Confluence database. Even if attachment storage is not in the database, Confluence must still serve the media files which places unnecessary load on the Confluence server. There are servers dedicated and optimized for delivering large, static files, and some that specialize in streaming media. Confluence users should be able to utilize these resources.

An administrative option should be added to allow for the removal of this restriction, which would allow the embedding multimedia content using a URL in a manner similar to images.

Unable to render embedded object: File (filename.mov) not found.

It could also be an option to allow the Confluence administrator to restrict the domains which can be referenced using a regular expression, so for example, you can allow references to internal servers on the intranet.