(cherry picked from commit 212582a835326dfe159599b0f8ef03a071de786b)

So that we can test in Nightly the feature to disable secure
boot, allowing Boxes to create and boot EFI VMs in more environments.
https://gitlab.com/libvirt/libvirt-glib/-/commit/a6db3f314510b4

This allows Boxes to boot EFI systems even when secure-boot is not
supported by the environment.

With this, users should be able to run GNOME OS and (soon) other
EFI-only systems in the distro-packaged version of Boxes of their
choice.

While the Flatpak version of Boxes currently handles well secure-boot,
distros have not. Just a few distros support EFI and provide the
proper environment for the virt stack that Boxes needs to boot EFI
VMs consistently.

The distro-packaged version of Boxes runs without the constrains
of the Flatpak sandbox, and can provide additional (useful) features
such as USB redirection, Network Bridge, etc...

This will set the xdg-shell app_id correctly. See [1].

It also sets wmclass correctly to the APPLICATION_ID rather than
gnome-boxes.

[1] https://docs.gtk.org/gtk4/migrating-3to4.html#set-a-proper-application-id

At the moment the request portal wrapper is using the application id as
a window identifier. This is an invalid window identifier, this string
should start with either `x11:` or `wayland:`. See [1].

There is a related report at [2].

[1] https://flatpak.github.io/xdg-desktop-portal/docs/window-identifiers.html
[2] https://github.com/flathub/org.gnome.Boxes/issues/95

Fixes: https://gitlab.gnome.org/GNOME/gnome-boxes/-/issues/1031

Currently, we fallback to default resources only when we cannot detect
the OS, but not when a detected OS doesn't provide any recommended
resources. This fix should address the later part too. ( where default
values in UI during VM creation for RAM is 64 MiB and default Storage
Limit is 0 GiB )

- Use appstreamcli to validate the appdata file
- Add the `<developer><name>` tag
- Mark the `<developer_name>` as deprecated
- Add vcs-browser URL

It's not exactly clear why we hit this case. Adding a 'null' check for
now to prevent the entire app from crashing (due to some cloning VMs)

Refer https://github.com/flathub/org.gnome.Boxes/issues/90

Fixes #1029

We need the VM assistant window to stay open so 'show_error()' can
display the error message, when 'Create' button is clicked.

../src/assistant/os-chooser-row.vala:114.9-114.22: warning: implicit .begin is deprecated
  114 |         on_os_selected (os);
      |         ^~~~~~~~~~~~~~

On NixOS, packages are immutable so the `share/gnome-boxes/unattended/disk.img` file would have 0444 mode when copied.
As a result, express installation would fail due to permission error.

Let’s use the default permissions to work around this.

Fixes: https://gitlab.gnome.org/GNOME/gnome-boxes/-/issues/880

It should be empty, but not null.

Fixes #1081.