Add an ability to automatically kill entities

## Describe your suggestion
Just like #follow command you should be able to select a player or an entity (probably only passive mobs)

## Settings

> ~~doCrits = will do critical hits in a not legit way (some packet magic)~~
> ~~doCritsLegit = will do critical hits in a legit way (jump and hit)~~

## Context
Sometimes you need some food, and don't feel like killing animals manually, you can do #kill entity pig and get food

## Final checklist
- [x] I know how to properly use check boxes
- [x] I have not used any OwO's or UwU's in this issue.