Add packit configuration

See <https://packit.dev>. This will gradually replace our cockpituous
configuration.

Closes #151

packit.yaml

@@ -0,0 +1,8 @@
+specfile_path: cockpit-podman.spec
+synced_files:
+  - cockpit-podman.spec
+upstream_project_name: cockpit-podman
+downstream_package_name: cockpit-podman
+actions:
+  post-upstream-clone: make cockpit-podman.spec
+  create-archive: make dist-gzip