Filter clause is not working on AnnoyModelFetcher

Below query should filter all edges that have property 'score' smaller than 0.1 but current implementation return edges with larger score property value than 0.1.

{
  s2graph {
    user(id: 0) {
      friends(limit: 10, filter: "score < 0.1") {
        user {
          id
        }
      }
    }
  }
}

After a look through the current master, I found out Where parser and EdgeTransformer are processed on AsynchbaseEdgeFetcher and RocksEdgeFetcher by calling StorageIO.toEdges method, but this is missing on AnnoyModelFetcher.

I suggest to extract `Where` and `EdgeTransformer` from StorageIO.toEdges to helper so other Fetcher implementation can easily use this helper to apply them correctly.