CI: Refresh OpenSUSE Tumbleweed container

Existing as suse:opensuse-tumbleweed is a historical quirk, and adjusted for
consistency with all the other containers.

Make it non-root, use heredocs for legibility, and use the zypper long names
for the benefit of those wondering what was being referenced or duplicated.

Trim the dependencies substantially.  Testing docs isn't very interesting and
saves a lot of space.  Other savings come from removing a huge pile of
optional QEMU dependencies (QEMU just needs to build the Xen parts to be
useful here, not have a full GUI environment).

Finally, there where some packages such as bc, libssh2-devel, libtasn1-devel
and nasm that I'm not aware of any reason to have had, even historically.

This shaves 1G off the size of the container:

  registry.gitlab.com/xen-project/xen/opensuse  tumbleweed-x86_64      1.39GB
  registry.gitlab.com/xen-project/xen/suse      opensuse-tumbleweed    2.35GB

Furthermore, identify which components of the build use which dependencies,
which will help managing them in the future.

Thanks to Olaf Hering for dependency fixes that have been subsumed into this
total overhaul.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
Release-Acked-By: Oleksii Kurochko <oleksii.kurochko@gmail.com>

automation/scripts/containerize

@@ -43,7 +43,7 @@ case "_${CONTAINER}" in
     _bionic) CONTAINER="${BASE}/ubuntu:bionic" ;;
     _xenial) CONTAINER="${BASE}/ubuntu:xenial" ;;
     _opensuse-leap|_leap) CONTAINER="${BASE}/suse:opensuse-leap" ;;
-    _opensuse-tumbleweed|_tumbleweed) CONTAINER="${BASE}/suse:opensuse-tumbleweed" ;;
+    _opensuse-tumbleweed|_tumbleweed) CONTAINER="${BASE}/opensuse:tumbleweed-x86_64" ;;
 esac
 
 # Use this variable to control whether root should be used