[FIX] survey: mess with JS loading

Since yesterday, JS bundles are now loaded at the end of the webpage.
Old-style modules that hardlink js code in the <head> section are now
broken since they use jQuery's $.
[FIX] Report: compatibility issues on Windows

This commit fixes two different issues specific to Windows:
* NamedTemporaryFile behavior, requiring a file to be closed before being
  accessed a second time
* Wkhtmltopdf crash when the document's dpi is inferor to 96
[FIX] Packaging: Windows: fix logging to file