privacy: Use drop-in config component for /etc files

Tests:

- Config files are all symlinks in /etc/
- popularity-contest shows VENDOR:FreedomBox

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

debian/freedombox.maintscript

@@ -122,3 +122,4 @@ rm_conffile /etc/mediawiki/FreedomBoxStaticSettings.php 23.10~
 rm_conffile /etc/apache2/conf-available/minidlna-freedombox.conf 23.10~
 rm_conffile /etc/NetworkManager/dispatcher.d/10-freedombox-batman 23.10~
 rm_conffile /etc/pagekite.d/90_freedombox_certs.rc 23.10~
+rm_conffile /etc/dpkg/origins/freedombox 23.10~

plinth/modules/privacy/__init__.py

@@ -6,6 +6,7 @@ from django.utils.translation import gettext_noop
 
 from plinth import app as app_module
 from plinth import menu
+from plinth.config import DropinConfigs
 from plinth.modules.backups.components import BackupRestore
 from plinth.package import Packages
 
@@ -19,7 +20,7 @@ class PrivacyApp(app_module.App):
 
     app_id = 'privacy'
 
-    _version = 1
+    _version = 2
 
     can_be_disabled = False
 
@@ -41,6 +42,11 @@ class PrivacyApp(app_module.App):
         packages = Packages('packages-privacy', ['popularity-contest', 'gpg'])
         self.add(packages)
 
+        dropin_configs = DropinConfigs('dropin-configs-privacy', [
+            '/etc/dpkg/origins/freedombox',
+        ])
+        self.add(dropin_configs)
+
         backup_restore = BackupRestore('backup-restore-privacy',
                                        **manifest.backup)
         self.add(backup_restore)