**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.
ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t ) const override
    {
        const ColumnPtr & column = arguments[0].column;
        if (const ColumnUInt32 * col = typeid_cast<const ColumnUInt32 *>(column.get()))
        {
            const ColumnUInt32::Container & vec_in = col->getData();
            auto col_res = ColumnString::create();
            ColumnString::Chars & vec_res = col_res->getChars();
            ColumnString::Offsets & offsets_res = col_res->getOffsets();
            vec_res.resize(vec_in.size() * (IPV4_MAX_TEXT_LENGTH + 1)); 
            offsets_res.resize(vec_in.size());
            char * begin = reinterpret_cast<char *>(vec_res.data());
            char * pos = begin;
            for (size_t i = 0; i < vec_in.size(); ++i)
            {
                DB::formatIPv4(reinterpret_cast<const unsigned char*>(&vec_in[i]), pos, mask_tail_octets, "xxx");
                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 FunctionIPv4StringToNum : public IFunction