[Feature Request] Improve rule ordering logic

### Summary:

Current [logic behind the rule ordering](https://github.com/gustavo-iniguez-goya/opensnitch/wiki/Rules) is far from intuitive (in particular, the notion of "deny always wins"). I propose two possible ways to improve it:

1. Ordering by the rule number. Each rule has an integer assigned to it, evaluate from small to large.

2. "First matching rule wins" -- an approach used in Mikrotik RouterOS, effectively first rule that matches the packet is used, then if fall back onto the default action if nothing matched.