chore: move fields from xmodule to core

Author: irtazaakram

setup.cfg

@@ -8,5 +8,9 @@
 # E501: line too long
 # E722: do not use bare except, specify exception instead
 #   We catch this with pylint, don't need 2 reports of the same issue
-ignore=E501,E402,E722
+# W503: line break before binary operator
+#   Ignored because Black intentionally formats line breaks *before*
+#   binary operators, following the updated PEP 8 recommendation.
+#   Keeping W503 enabled would cause false positives on Black-formatted code.
+ignore=E501,E402,E722,W503
 exclude=docs/*,.tox/