**Use case**

Viewing binary data such as bitmasks, hashes, internal representation of IEEE-754 numbers, etc.
Mostly for debugging.

**Describe the solution you'd like**

Similar to `hex`/`unhex`.

`bin` - returns a string with `0` and `1`. Bits are in "human" order, most significant first. Most significant zero bits are not printed (except the case with single zero).

**Describe alternatives you've considered**

Now I have to run interactive `python` from command line, but I will be more happy using ClickHouse.

**Caveats**

The name `bin` may suggest that the function will "split data into bins" but it is completely unrelated.
if (col_in->getN() != IPV6_BINARY_LENGTH)
                throw Exception("Illegal type " + col_type_name.type->getName() +
                                " of column " + col_in->getName() +
                                " argument of function " + getName() +
                                ", expected FixedString(" + toString(IPV6_BINARY_LENGTH) + ")",
                                ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
            const auto size = col_in->size();
            const auto & vec_in = col_in->getChars();
            auto col_res = ColumnString::create();
            ColumnString::Chars & vec_res = col_res->getChars();
            ColumnString::Offsets & offsets_res = col_res->getOffsets();
            vec_res.resize(size * (IPV6_MAX_TEXT_LENGTH + 1));
            offsets_res.resize(size);
            auto * begin = reinterpret_cast<char *>(vec_res.data());
            auto * pos = begin;
            for (size_t offset = 0, i = 0; offset < vec_in.size(); offset += IPV6_BINARY_LENGTH, ++i)
            {
                formatIPv6(reinterpret_cast<const unsigned char *>(&vec_in[offset]), pos);
                offsets_res[i] = pos - begin;
            }
            vec_res.resize(pos - begin);
            return col_res;
        }
        else
            throw Exception("Illegal column " + arguments[0].column->getName()
                + " of argument of function " + getName(),
                ErrorCodes::ILLEGAL_COLUMN);
    }
};
class FunctionCutIPv6 : public IFunction