[8.x] Adds possibility to customize child model route binding resolution

[marvin-wtt]

This is an approach to allow the user to define a custom model binding query by overwriting the added function resolveRouteBindingQuery. It is needed if lookup of the model cannot be achieved by comparing the value with the field.
The actual problem is briefly explained in #39779

For an for me unknown reason, the test models actually return a model instead of a relation. I considered this even though I don't understand the intention for that.

I am open for other ideas

[marvin-wtt]

An example for localized fields where the translations are stored as JSON:

class TestModel extends Model
{
    // ...

    public function resolveRouteBindingQuery($query, $value, $field = null): Builder
    {
        return $query->where("{$field}->{$this->getLocale()}", $value);
    }
}

[iamgergo]

I had a similar attempt here: #34134, however it was a BC.

An addition like this, would be very handy in my opinion, thanks for the PR.