refactor: share common files between images; trim fedora-remote for a VM

- Move Kanidm/flatpak/finalize.d/sshd files to images/shared/{files,repos}
  and have build.sh overlay them for every image.
- fedora-remote: aggressive hardware trim (no firmware, no kernel-modules-extra,
  no non-QEMU guest agents), keep + enable qemu-guest-agent (Proxmox).
- Fixes the missing package-list (release step) for fedora-remote.

images/shared/repos/44/network-idm.repo

@@ -0,0 +1,9 @@
+[network_idm]
+name=Identity Management related tools (Fedora 44)
+baseurl=https://download.opensuse.org/repositories/network:/idm/Fedora_44/
+type=rpm-md
+skip_if_unavailable=False
+gpgcheck=1
+repo_gpgcheck=0
+enabled=1
+gpgkey=https://download.opensuse.org/repositories/network:/idm/Fedora_44/repodata/repomd.xml.key