Bug#819013: debsources: deduplicate the html setting the background image

[Matthieu Caneill <matt@brokenwa.re>]

Package: qa.debian.org
Severity: minor
Tags: newcomer
User: qa.debian.org@packages.debian.org
Usertags: debsources

The few lines of html setting the background image on some pages are
duplicated many times (try grepping bg_wrapper).
It would be nice to see this in a separate file that would be included
on demand!

Cheers,
--
Matthieu

-- System Information:
Debian Release: stretch/sid
  APT prefers testing-updates
  APT policy: (500, 'testing-updates'), (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 4.3.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)