Improved usability for ODF users by providing the default values as XML

We once moved the default values from the RelaxNG grammar to specification in ODF 1.2 - AFAIR due to the insertion of the default values by XML parsers when using an XML grammar and blowing up the content esp. of tables.

We should provide a processable list in XML of those default values, for now, keeping the ODT specification as preceding normative entity in case of derivations of that XML file and the specification.

See on TC mailinglist https://lists.oasis-open.org/archives/office/202007/msg00003.html:
"We should not only be able to extract our default values for ODF 1.3 but provide them as a stand-alone file: OpenDocument-v1.3-cs02-part3-attribute-defaults.xml"