Issue 1544 - RFE - Add colored tags
    
        I only extended the base Tag
        object to include color, projectID, and a unique id.  Then I removed the
        dependency of the issue from the tag for working in the ui.   Otherwise
        tags were only visible if an issue contained that tag.  This also meant
        you could not add, edit, or remove a tag unless you had already added
        one to an issue.  So in my patch it updated the setting.html page to
        show all tags (whether or not they existed in an issue).  You can add,
        edit and delete them.  They also automatically update all the issues in
        that project with the color/name change.  This is also reflected in both
        issues.html & issue.html.
    
        I also added a unique identifier to each tag(tag_id) - this allows every
        project to use the same name with its own unique color.  There are no
        conflicts since the primary key is now the unique identifier(tag_id)
        instead of the tag name(tag).
    
        This patch enforces that tags are only created from the settings page.
    
        This patch is missing the complete alembic migration script.