Support Lua-scripts to generate random data for producing

To generate some specific data would be great to support Lua-script.

For example, if my script is in `funcs.lua:`
```lua
function randomCardNumber() {
    return "4242424242424242"
}
```
It can be passed to input like:
```shell
$ protokaf produce CardRequest \
  --lua funcs.lua
  --data '{"card": {{randomCardNumber | quote}}}'
  ...
```