New HTML output mode for Gitlab CI

[Felix Lechner <felix.lechner@lease-up.com>]

Hi,

Here is quick heads up that Lintian has a new output mode for
standalone HTML pages.  The mode will be used with Gitlab Pages to
offer graphical Lintian results in the majority of Gitlab CI
instances.

The functionality may reduce user reliance on lintian.d.o.

In Lintian, the new mode is invoked with '--exp-output format=html'.
After piping, please use your favorite browser with a 'file:' URL to
look at the results.

A new Lintian release would be nice for continued work in deployed
instances, but due to Bug#964111 I am not sure Lintian will currently
build. Perhaps it's better to hold off for now.

I already made several adjustments to our test suite and am not sure
which, if any, additional steps should be taken to accommodate Dpkg.

Please have a good weekend (it's a big holiday, for some)!

Kind regards
Felix Lechner