Ability to get committee members via RPC

[roman-khimov]

Summary or problem description
After the governance changes we now have a new entity, committee. It's an important entity in Neo but there is currently no easy way to get data about its members via RPC (counting candidates votes is not considered).

Do you have any solution you want to propose?
I see two main options here:

1. Add an explicit getcommittee RPC call that would return committee members (probably with some flag signifying validators).
2. Modify getvalidators RPC call, remove "active" field and add "incommittee" and "isvalidator" fields where isvalidator would have the same meaning as active previously and incommittee would be true for the members of committee.

But maybe there is some better way.

Where in the software does this update applies to?

• RPC (HTTP)