Legacy schemas

The following legacy schemas and not part of the most recent ASDF standard version:

• core/asdf-1.0.0
• core/column-1.0.0
• core/integer-1.0.0
• core/ndarray-1.0.0
• core/table-1.0.0
• fits/fits-1.0.0
• time/time-1.0.0
• time/time-1.1.0
• unit/quantity-1.1.0