#420 Warn moderator if adding a new author to a Series

[Ahasuerus]

The Edit Title approval page should warn the approving moderator if (a) the editor is adding this title to a series, and (b) the series already exists and (c) the title's author(s) do not have pre-existing entries in the series. This combination of factors may indicate that there is a different series with the same name on file.