Filtering for NOT

[alkampfergit]

In some scenario I need not only to be able to filter for memories that have a specific value in one of the tag with ByTag, but I want also NotByTag, meaning that I want to return only memories that has not a value in a specific Tag.

This is expecially useful when you filter for security, where you have logic like: this is accessed by group X but never accessed by an ExternalUser.