stages/authconfig: run authconfig

This applies the default authconfig settings to the tree.

Note that the `/backups` directory is removed. The tool creaset
this, and by default it should not exist, so this should be a
noop. However, if you run this on a tree with existing backups,
they would be lost.

stages/org.osbuild.authconfig

@@ -0,0 +1,42 @@
+#!/usr/bin/python3
+"""
+Configure authentication sources using authconfig.
+
+Applies the default settings. Backups are cleared.
+
+Notes:
+  - Requires 'chroot' in the buildroot.
+  - Runs the 'authconfig' binary from the image in the chroot.
+"""
+
+
+import shutil
+import subprocess
+import sys
+
+import osbuild.api
+
+
+SCHEMA = """
+"additionalProperties": false,
+"description": "Configure authentication sources."
+"""
+
+
+def main(tree):
+    cmd = [
+        "/usr/sbin/chroot", tree,
+        "/usr/sbin/authconfig", "--nostart",  "--updateall"
+    ]
+
+    subprocess.run(cmd, check=True)
+
+    shutil.rmtree(f"{tree}/var/lib/authselect/backups", ignore_errors=True)
+
+    return 0
+
+
+if __name__ == '__main__':
+    args = osbuild.api.arguments()
+    r = main(args["tree"])
+    sys.exit(r)