Add ability to auto convert a foreach loop over a query to IJobEntity

Basically add a code action to transform something like:

```cs
foreach(var (RefRO<ComponentA> a, RefRW<ComponentB> b, Entity entity) in SystemAPI.Query<RefRO<ComponentA>, RefRW<ComponentB>>().WithEntityAccess() {
    ...
}
```

to 

```cs
internal partial struct JOB_NAME: IJobEntity {
    private void Execute(in ComponentA a, ref ComponentB b, Entity entity) {
        ...
    }
}
```