Add a streaming data input/output object for http.client. The
input/output object can be created using the same methods and the
same options as a normal request, but with a new option
{chunked = true}.

Closes #7845

@TarantoolBot document
Title: Stream input/output interface for http.client

An uncompleted io object has only headers and cookies fields. A
completed io object has the same fields as a normal request, but
without the `body` field.

The io object interface looks like the socket object interface
and should have the same description:

```
io_object:read(chunk[, timeout])
io_object:read(delimiter[, timeout])
io_object:read({chunk = chunk, delimiter = delimiter}[, timeout])
io_object:write(data[, timeout])
```

The difference is in the method `finish`. Unlike socket:close()
it has an optional parameter `timeout`:

```
io_object:finish([timeout])
```

Be careful, the call may yield a fiber. The idea is to wait
until a HTTP connection is finished by the server-side or
force finish the connection from client-time after a timeout
value.

The default timeout value is 10 seconds for all methods.

Usage example:

```lua
local io = httpc:post(url, nil, {chunked = true})

local write_chan = fiber.channel()
fiber.new(function()
    fiber.name("write to " .. url)
    while true do
        local data = write_chan:get()
        if data == nil then
            break
        end
        io:write(data, 1)
    end
end)

local recvdata
while recvdata = io:read('\r\n', 1) do
    local decoded = json.decode(recvdata)
    if condition(decoded) then
        write_chan:put(data)
    end
    if condition(decoded) then
        io:finish(1)
    end
end
write_chan:close()
```

See also:
* https://www.tarantool.io/en/doc/latest/reference/reference_lua/socket/#lua-function.socket_object.read
* https://github.com/tarantool/tarantool/issues/7845#issuecomment-1298538412
* https://github.com/tarantool/tarantool/issues/7845#issuecomment-1298821779