Add new WitnessScope: Rules

[erikzhang]

Replace #2596

[Jim8y]

Why conditions are under the payload folder? Too many files in this folder, and it is hard to locate the condition files.

[erikzhang]

Why conditions are under the payload folder? Too many files in this folder, and it is hard to locate the condition files.

I've moved them to a new namespace.

[vncoelho]

I like this design, @erikzhang.
Much more flexible and powerful.

[roman-khimov]

It's an interesting generalization that seems to cover #2583 problem well and also cases discussed in #2596. My primary concern would be is this simple enough to explain to developers that are gonna create transactions using this scope?

[Jim8y]

My primary concern would be is this simple enough to explain to developers that are gonna create transactions using this scope?

We need documents and samples for this~~

[shargon]

The code looks good, but what about something like a verification script. We push The Calling, Current and ExecutingHash (3 ByteString) and the script returns if it's allowed or not?

[erikzhang]

The code looks good, but what about something like a verification script. We push The Calling, Current and ExecutingHash (3 ByteString) and the script returns if it's allowed or not?

Then we have to consider issues such as endless loops and permissions.