security: Enable backup/restore

Currently only the restricted login setting is backed up and restored. Fail2Ban
needs ability to backup and restore state of services.

Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

functional_tests/features/security.feature

@@ -31,3 +31,11 @@ Scenario: Disable restricted console logins
   Given restricted console logins are enabled
   When I disable restricted console logins
   Then restricted console logins should be disabled
+
+Scenario: Backup and restore security
+  When I enable restricted console logins
+  And I create a backup of the security app data
+  And I disable restricted console logins
+  And I export the security app data backup
+  And I restore the security app data backup
+  Then restricted console logins should be enabled

plinth/modules/security/__init__.py

@@ -23,6 +23,8 @@ from django.utils.translation import ugettext_lazy as _
 from plinth import actions
 from plinth.menu import main_menu
 
+from .manifest import backup
+
 version = 4
 
 is_essential = True

plinth/modules/security/manifest.py

@@ -0,0 +1,27 @@
+#
+# This file is part of FreedomBox.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+"""
+Application manifest for security.
+"""
+
+from plinth.modules.backups.api import validate as validate_backup
+
+backup = validate_backup({
+    'config': {
+        'files': ['/etc/security/access.conf']
+    }
+})