Fix German date format

[moewew]

German dates require a different logic for comp dates since the order
is different from American-style dates.
Grouped \blx@metadateinfo.

Test against

\documentclass{article}
\usepackage[ngerman]{babel}
\usepackage{csquotes}
\usepackage{filecontents}
\begin{filecontents*}{\jobname.bib} 
@ARTICLE{7.01:8,
  AUTHOR         = {Richard Clay},
  TITLE          = {Science vs. Ideology},
  SUBTITLE       = {Psychologists Fight Back About the Misuse of Research},
  JOURNALTITLE   = {Monitor on Psychology},
  VOLUME         = {39},
  NUMBER         = {6},
  DATE           = {2008-06},
  URL            = {http://www.apa.org/monitor/},
}
@ARTICLE{7.01:8de,
  AUTHOR         = {Richard Clay},
  TITLE          = {Science vs. Ideology},
  SUBTITLE       = {Psychologists Fight Back About the Misuse of Research},
  JOURNALTITLE   = {Monitor on Psychology},
  VOLUME         = {39},
  NUMBER         = {6},
  DATE           = {2008-06},
  URL            = {http://www.apa.org/monitor/},
  URLDATE           = {2008-06},
}
@ARTICLE{7.01:8deday,
  AUTHOR         = {Richard Clay},
  TITLE          = {Science vs. Ideology},
  SUBTITLE       = {Psychologists Fight Back About the Misuse of Research},
  JOURNALTITLE   = {Monitor on Psychology},
  VOLUME         = {39},
  NUMBER         = {6},
  DATE           = {2008-06-05},
  URLDATE           = {2008-06-05},
  URL            = {http://www.apa.org/monitor/},
}
@ARTICLE{7.01:8derangeday,
  AUTHOR         = {Richard Clay},
  TITLE          = {Science vs. Ideology},
  SUBTITLE       = {Psychologists Fight Back About the Misuse of Research},
  JOURNALTITLE   = {Monitor on Psychology},
  VOLUME         = {39},
  NUMBER         = {6},
  DATE           = {2008-06-05/2008-06-07},
  URLDATE           = {2008-06-05/2008-06-07},
  URL            = {http://www.apa.org/monitor/},
}
@ARTICLE{7.01:8derangemonth,
  AUTHOR         = {Richard Clay},
  TITLE          = {Science vs. Ideology},
  SUBTITLE       = {Psychologists Fight Back About the Misuse of Research},
  JOURNALTITLE   = {Monitor on Psychology},
  VOLUME         = {39},
  NUMBER         = {6},
  DATE           = {2008-06-05/2008-07-05},
  URL            = {http://www.apa.org/monitor/},
  URLDATE           = {2008-06-05/2008-07-05},
}
@ARTICLE{7.01:8derangeyear,
  AUTHOR         = {Richard Clay},
  TITLE          = {Science vs. Ideology},
  SUBTITLE       = {Psychologists Fight Back About the Misuse of Research},
  JOURNALTITLE   = {Monitor on Psychology},
  VOLUME         = {39},
  NUMBER         = {6},
  DATE           = {2008-06-05/2009-07-05},
  URL            = {http://www.apa.org/monitor/},
  URLDATE           = {2008-06-05/2009-07-05},
}
\end{filecontents*}

\usepackage[backend=biber,style=apa]{biblatex}
\addbibresource{\jobname.bib} 

\begin{document}
\textcite{7.01:8de,7.01:8deday,7.01:8derangeday,7.01:8derangemonth,7.01:8derangeyear}
\printbibliography
\end{document}

to see the difference. The test files shows that even for american the URL date ranges can look off (but then again, URL dates should probably never be ranges).

I suspect many other localisations that don't use American-style dates will also need changes.