Make villager transportation with minecart easier

I'm glad to see changes in the currently very broken villager trading system. However, I think we should fix villager transportation before requiring breeding villagers in different biomes.

There are many good suggestions for early game villager transportation methods, but as a forever world player, I'd like to see improvements for late game methods.

Here are my suggestions:

1. Make it easier to get villagers into minecart. Instead of pushing them into minecart, we need a way to let villagers get into minecart willingly. This makes sense as well because villagers are supposed to be creatures of intelligence, and can communicate with players.

2. Make entities in minecart go through nether portals and end portals easier. This helps long distance villager transportation.