Implement unic-ucd-unihan

[eyeplum]

Provides access to:

• Unihan_DictionaryIndices
• Unihan_DictionaryLikeData
• Unihan_IRGSources
• Unihan_NumericValues
• Unihan_OtherMappings
• Unihan_RadicalStrokeCounts
• Unihan_Readings
• Unihan_Variants

References:

• https://www.unicode.org/reports/tr38/tr38-25.html

[eyeplum]

Please refer to #225 for a possible way to implement this.