Create the 'About content' widget

There should be an aboutcontent widget that has 2 different tabs. The first tab is the Details tab and shows the metadata of the content (title, description, url, created by). When a description is not available, it should not be shown. The second tab is the Shared with tab and shows the list of members of the content.
I really think we should keep this in here to keep the padding and margin consistent across widgets. It doesn't look good to have the text in aboutcontent or the grid in contentshared stick to the bottom of the modal. I know this is an empty div but it beats compromising the look and consistency.