Add command line script for catalog enrichment

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To download and inspect PICA records from K10plus catalog and to check and add decompositions.

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Algorithm:

• Optionally get a selected DDC number to decompose
• Read PICA records
• Get all DDC numbers in the record
• Optionally filter to the selected DDC number only
• Get complete decomposition (and cache it)
• Check whether decomposition is trivial (base number = table number), skip in this case
• Get existing decomposition in the record and compare
• Create and emit Record diff

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Actual catalog enrichment should wait before #31 has been done.

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Now included in directory k10plus.