Add a dedicated folder for plugin data

gajim/common/configpaths.py

@@ -197,6 +197,7 @@ class ConfigPaths:
             ('SECRETS_FILE', 'secrets', PathLocation.DATA, PathType.FILE),
             ('MY_PEER_CERTS', 'certs', PathLocation.DATA, PathType.FOLDER),
             ('DEBUG', 'debug', PathLocation.DATA, PathType.FOLDER),
+            ('PLUGINS_DATA', 'plugins_data', PathLocation.DATA, PathType.FOLDER),
 
             # Config paths
             ('CONFIG_FILE', 'config', PathLocation.CONFIG, PathType.FILE),