[API CHANGE]: extends the css.configuration.XReadWriteAccess in an incompatible
way, but that is unpublished, has been commented as "still unpublished and
unstable," and was specifically introduced for internal use by the simplified
configuration access, so should not affect 3rd party code.
Change-Id: I99ce045f5bd8c598e689d46fb0d3626dfaa6d0a0
see https://gerrit.libreoffice.org/#/c/3367/
and Change-Id: I00c96fa77d04b33a6f8c8cd3490dfcd9bdc9e84a for details
Change-Id: I199a75bc4042af20817265d5ef85b1134a96ff5a