fedora-cosmic: add OBS network:idm repo for Kanidm packages

Kanidm is not in the Fedora repos; it ships from the openSUSE OBS
network:idm project. Add per-distro repo files (Fedora_44 / Fedora_Rawhide)
and teach build.sh to overlay repos/<distro>/*.repo.

images/fedora-cosmic/manifest.yaml

@@ -21,6 +21,9 @@ ref: fedora-cosmic/${releasever_ref}/${basearch}/cosmic
 repos:
   # Local repo generated by build.sh from the token2-fido-bridge GitHub release.
   - token2-fido-bridge
+  # Kanidm packages (OBS network:idm); distro-specific repo file selected by
+  # build.sh from repos/<distro>/.
+  - network_idm
 
 include:
   - cosmic-atomic.yaml

images/fedora-cosmic/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

images/fedora-cosmic/repos/rawhide/network-idm.repo

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