Remove usage of cfg message from Field component

[emil14]

It's possible to have normal inport like path that takes list<string>

What if user pass incorrect path? Should Field have err outport? No, it should panic. User should not use field in the first place. We need to add it to its description.

Problems

Runtime overhead

This is simplicity vs performance kind of tradeoff

1. We need to allocate a message container which is a little bit bigger than native go slice
2. We need to use network transmission machinery to make it work

[emil14]

I would like to add that runtime overhead of const is itself a problem regardless this specific case. See #681 for details