Allays can repair held tools over time

I've been thinking about tool durability for a while, and I despise how efficient it is to exploit their regenerative abilities using infestation potions to repair your tools. I think there should be a better way to repair your tools in the game. In a discussion with my Brother, he thought Allay's regenerative abilities feel like an opportunity to do that.

3 parts to this:
- They should repair without mending, but very slowly.

- Mending will increase the rate of repair, but it should still be relatively slow. I don't want to replace the need for tool repair outright, but a slow trickle is nice and interesting.

- This should not rely on being in a loaded chunk. There should be some type of mechanic to compare how many ticks have gone by since it was handed the tool, and use that to repair it. I'm thinking it needs to be this way because it allows you to have toolsets you swap out and not require you to bring your allay with you.

An interesting other thought to teach the player this organically: Have allays in illager bases holding partially broken crossbows sometimes.