Looks like bfloat16 quantiles don't provide a way to specify the weight:

```sql
SELECT quantileBFloat16Weighted(0.5)(number, number)
FROM numbers(100)

Received exception from server (version 21.8.3):
Code: 46. DB::Exception: Received from localhost:9000. DB::Exception: Unknown function quantileBFloat16Weighted
```

But I expect it to work the same way as tdigest:

```sql
SELECT quantileTDigestWeighted(0.5)(number, number)
FROM numbers(100)

Query id: ea66ede3-afc6-4e5d-8949-2da5970e1349

┌─quantileTDigestWeighted(0.5)(number, number)─┐
│                                     70.35461 │
└──────────────────────────────────────────────┘
```

/cc @RedClusive just in case :)
{
        this->data(place).merge(this->data(rhs));
    }
    void serialize(ConstAggregateDataPtr __restrict place, WriteBuffer & buf) const override
    {
        
        this->data(const_cast<AggregateDataPtr>(place)).serialize(buf);
    }
    void deserialize(AggregateDataPtr __restrict place, ReadBuffer & buf, Arena *) const override
    {
        this->data(place).deserialize(buf);
    }
    void insertResultInto(AggregateDataPtr __restrict place, IColumn & to, Arena *) const override
    {
        
        auto & data = this->data(place);
        if constexpr (returns_many)
        {
            ColumnArray & arr_to = assert_cast<ColumnArray &>(to);
            ColumnArray::Offsets & offsets_to = arr_to.getOffsets();
            size_t size = levels.size();
            offsets_to.push_back(offsets_to.back() + size);
            if (!size)
                return;
            if constexpr (returns_float)
            {
                auto & data_to = assert_cast<ColumnVector<FloatReturnType> &>(arr_to.getData()).getData();