documents: fix generic file icon, re #4235

git-svn-id: svn://develop.studip.de/studip/trunk@31122 c5b85792-5220-0410-ad23-ed5b6b8ad999
documents: fallback to file name if no specific name is given for an uploaded file, fixes #4500

git-svn-id: svn://develop.studip.de/studip/trunk@31123 c5b85792-5220-0410-ad23-ed5b6b8ad999
documents: remove db engine declaration from create statements, re #4235

git-svn-id: svn://develop.studip.de/studip/trunk@31124 c5b85792-5220-0410-ad23-ed5b6b8ad999