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 :)
#include <AggregateFunctions/AggregateFunctionQuantile.h>
#include <AggregateFunctions/AggregateFunctionFactory.h>
#include <AggregateFunctions/Helpers.h>
#include <Core/Field.h>
namespace DB
{
struct Settings;
namespace ErrorCodes
{
    extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}
namespace
{
template <typename Value, bool float_return> using FuncQuantile = AggregateFunctionQuantile<Value, QuantileReservoirSampler<Value>, NameQuantile, false, std::conditional_t<float_return, Float64, void>, false>;
template <typename Value, bool float_return> using FuncQuantiles = AggregateFunctionQuantile<Value, QuantileReservoirSampler<Value>, NameQuantiles, false, std::conditional_t<float_return, Float64, void>, true>;
template <typename Value, bool float_return> using FuncQuantileDeterministic = AggregateFunctionQuantile<Value, QuantileReservoirSamplerDeterministic<Value>, NameQuantileDeterministic, true, std::conditional_t<float_return, Float64, void>, false>;
template <typename Value, bool float_return> using FuncQuantilesDeterministic = AggregateFunctionQuantile<Value, QuantileReservoirSamplerDeterministic<Value>, NameQuantilesDeterministic, true, std::conditional_t<float_return, Float64, void>, true>;
template <typename Value, bool _> using FuncQuantileExact = AggregateFunctionQuantile<Value, QuantileExact<Value>, NameQuantileExact, false, void, false>;
template <typename Value, bool _> using FuncQuantilesExact = AggregateFunctionQuantile<Value, QuantileExact<Value>, NameQuantilesExact, false, void, true>;
template <typename Value, bool _> using FuncQuantileExactLow = AggregateFunctionQuantile<Value, QuantileExactLow<Value>, NameQuantileExactLow, false, void, false>;
template <typename Value, bool _> using FuncQuantilesExactLow = AggregateFunctionQuantile<Value, QuantileExactLow<Value>, NameQuantilesExactLow, false, void, true>;
template <typename Value, bool _> using FuncQuantileExactHigh = AggregateFunctionQuantile<Value, QuantileExactHigh<Value>, NameQuantileExactHigh, false, void, false>;
template <typename Value, bool _> using FuncQuantilesExactHigh = AggregateFunctionQuantile<Value, QuantileExactHigh<Value>, NameQuantilesExactHigh, false, void, true>;
template <typename Value, bool _> using FuncQuantileExactExclusive = AggregateFunctionQuantile<Value, QuantileExactExclusive<Value>, NameQuantileExactExclusive, false, Float64, false>;
template <typename Value, bool _> using FuncQuantilesExactExclusive = AggregateFunctionQuantile<Value, QuantileExactExclusive<Value>, NameQuantilesExactExclusive, false, Float64, true>;