Add separate good/bad sink configurations

[pondzix]

Old style:

streams {
      good = "good-name"
      bad = "bad-name"
      buffer {...} //shared by good and bad
      sink {...} //shared by good and bad
    }

now becomes:

streams {
      good {
        name: "good-name"
        buffer {...}
        // rest of the sink config, previously in the `sink` section...
      }
      bad {
        name: "bad-name"
        buffer {...}
        // rest of the sink config, previously in the `sink` section...
      }
    }

• This PR is backward compatible, so the old style config is still supported.
• Removed enabled flag from sink config which seems to be no longer used.