roles_logic_sv2: refactor routing_logic module

[GitGab19]

This module is only really used by mining-proxy, since it's meant to provide some very opinionated features needed only by a pure Sv2 proxy.

It is very tied to selectors module, so both of them should be touched sequentially.

More specifically, this modules has to be moved to mining-proxy libs, together with its removal from handlers module, and adjustments on mining-proxy side.

The main adjustment on mining-proxy side is about checking the routing_logic value in the proxy, instead of doing it in the handlers.