Corrects links to manuals in many languages (issue 7311074)

[PhilEHolmes]

Reviewers: ,

Message:
Please review.

Description:
A number of the links on the Development pages for the various languages
point to pages that don't exist (e.g. the Czech page
http://lilypond.org/development.cs.html) or don't point to translated
pages when they do exist (e.g. http://lilypond.org/development.it.html).
 This patch _should_ fix many of these.  It's difficult to test
properly, since it relies on interactions between make doc in GUB and
make website on the server.  However, I believe it's a step forward and
would like to get it into master fairly quickly.

Please review this at https://codereview.appspot.com/7311074/

Affected files:
  M Documentation/cs/web/community.itexi
  D Documentation/cs/web/news-front.itexi
  D Documentation/hu/web/basic-authors.itexi
  M Documentation/hu/web/community.itexi
  M Documentation/it/web/community.itexi
  M Documentation/zh/web/community.itexi