Normalize Dewey Decimal Class (DDC) format from MARC records (ie 082 field)

@EdwardBetts I think this is your balliwick:

We seem to have inconsistent representation of DDC. Sometimes it's just the base class, sometimes the extended one, sometimes it includes a trailing publication-year. Sometimes it embeds spaces, periods, apostrophes, and/or slashes in various combinations. Surely these should be standardized.

Segmentation of the DDC numbers (as recorded in the LoC data) is discussed at https://www.loc.gov/aba/dewey/segmentation.html and its MARC 21 representation at the 082 field is discussed at https://www.loc.gov/marc/bibliographic/bd082.html

The OL records representation of DDC is, it seems, taken from this by https://github.com/internetarchive/openlibrary/blob/c36d243cb552fa4bb463aaaa4bd4e70f1d80860a/openlibrary/catalog/marc/build_record.py#L203

and built into an edition record by https://github.com/internetarchive/openlibrary/blob/c36d243cb552fa4bb463aaaa4bd4e70f1d80860a/openlibrary/catalog/marc/build_record.py#L505