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.
We're going to limit the scope of the clip changes for now. The leave group and join group functionality can be taken back out of the clip and reverted to the clip approach.