Move tar filter to file, add tests for it

config_app/config_util/tar.py

@@ -0,0 +1,14 @@
+from util.config.validator import EXTRA_CA_DIRECTORY
+
+def tarinfo_filter_partial(prefix):
+    def tarinfo_filter(tarinfo):
+        # remove leading directory info
+        tarinfo.name = tarinfo.name.replace(prefix, '')
+
+        # ignore any directory that isn't the specified extra ca one:
+        if tarinfo.isdir() and not tarinfo.name == EXTRA_CA_DIRECTORY:
+            return None
+
+        return tarinfo
+
+    return tarinfo_filter