Tune villager trading

At the moment, villager trading is way too op considering how easy it is to max villagers and how easy it is to obtain mending books, this overall hinders progress as powerful items can be easily obtained through trading within hours. First of all, i believe treasure items such as the mending and frostwalker books should be completely taken out of villager trades, this makes these op books way more harder to obtain by which makes them more valuable. The second thing, is that villager trading levelling up should take way longer than it should do right now, making levelling up villagers take long wouldnt be sufficient enough as it could be pretty boring to grind for that long, which is where quests come into play. Each village profession could come with quests that the player must complete in order to unlock more and better trades, which enables more engagement with the villagers and makes grinding for the trades way more fun. If however, a villager dies when it is levelled up quite a bit, it can drop its badge correlating to its level (either its stone, iron, gold, diamond, emerald badge it has), and can be put onto another villager with a profession so players don't have to worry about losing progress.