Old flatpak could build only master, as flatpak-meson
build has replaced it (taking its name).

Long live the flatpak ci

- Make Evince builds on each MR, according to Initiatives#1

Fixes #995

This reverts commit f99c5543.

* Set application id lowercase
* Make the daemon and application names match
* Make the icons and desktop files match the
  application id
* Keep the D-BUS interfaces backwards compatible,
  and enable
  the flatpak version to launch the daemon.
* Take care of translations after renaming files.

This commit also changes the application id for flatpak,
which is a compromise.

The current flatpak scripts runs the job using the manifest,
which retrieves and builds the source from git master. Therefore,
it is unhelpful to build the MR.

For the moment, we will build the flatpak module only for
commits on master. Once we fix the script, we can extend the
CI tests to run for MR as well.

Added new manual pipeline to test the building Evince with
its documentation in gtk-doc format.

Fallback to autotools to fine tune the image to build
with meson properly.

So we know that the build works for Flatpak as well.

Do not make check without gtk-doc enabled.

Use new docker image to build evince master. The image has all
packages needed to build with any option.