Added: config BOOK commands such as

/betterlibrarian book list

/betterlibrarian book add <id> <enchantment> <level> [weight] [min max]

/betterlibrarian book remove <id>

/betterlibrarian book enable <id>

/betterlibrarian book disable <id>

/betterlibrarian book set <id> <field> <value>

config FEATURE commands such as

/betterlibrarian feature <feature> [true|false]

config PRICING commands such as

/betterlibrarian pricing <default_min_emeralds|default_max_emeralds|require_book_item> <value>

Fixed: nothing 👍 (no bugs found)