box.execute doesn't support bind parameters with type 'decimal'

[knazarov]

How to reproduce:

#!/usr/bin/env tarantool

local decimal = require('decimal')

box.cfg{}

s = box.schema.space.create('S', {format = {{'I', 'integer'}, {'D', 'decimal'}}, if_not_exists=true})
_ = s:create_index('ii', {if_not_exists=true})

local res, err = box.execute("INSERT INTO s VALUES (1, ?)", {decimal.new(0)})

if err ~= nil then
   print(err)
   os.exit(1)
end

Actual result: Bind value type USERDATA for parameter 1 is not supported

[kyukhin]

Blocked by #4415