Librarian Trade Rebalance + Enchanting Tweak

The Librarian Trade Rebalance is absolutely a step in the right direction, especially when coupled with the Chase the Clouds drop. But lots of people are still going to dislike this, especially people in superflats or single-biome worlds. Here are some possible tweaks that are - I think - easier to implement and logically flow from the current system:

• Librarians should only sell level 1 enchanting books. 
• A reroll button should be added to the enchanting table that costs 1-3 lapis to use. 
• Placing an enchanting book on the librarian's lectern will make them sell the lowest-level enchant from that book at mid-to-high price.
• Lecterns should duplicate enchanted books and - to keep a logical consistency - are how you duplicate written books.
• Grindstones can be used to extract enchantments from tools into a book. If too op, grindstones extract one enchantment from a tool.

This expands the use of lapis, lecterns, and grindstones in a logical fashion, incentivizes the use of the full enchanting system, balances encouraging exploration with players who have less of a world to explore (superflats and single biomes), and should balance the system.