Implement crystal portals with optional Immersive Portals view (#77)

src/main/resources/data/rivencraft/loot_table/blocks/book_receptacle.json

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+{"type":"minecraft:block","pools":[{"rolls":1,"entries":[{"type":"minecraft:item","name":"rivencraft:book_receptacle"}]}]}

src/main/resources/data/rivencraft/recipe/book_receptacle.json

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+{"type":"minecraft:crafting_shaped","pattern":["CCC","C C","CCC"],"key":{"C":{"item":"rivencraft:crystal_block"}},"result":{"id":"rivencraft:book_receptacle","count":1}}