Allow WAB Add Data Widget to use Groups or Tags as Search Scope Options

[SusanHmel]

It would be useful if the scope options on the WAB Add Data Widget were customizable beyond allow/disallow My Content, and Portal Content.

Having the ability to filter content by a standard text such as Group Name or a Tag would be helpful for organizations that have large amounts of content to search through. 

Creating a tag for a specific set of layers is useful, but any content can be tagged with that tag. Content that is in a defined group could be managed but currently can't be solely located just by the group name or ID.