Speed improvement: blocklist before NGD

[dkoslicki]

Apply the blocklist for general items before overlaying with NGD. Eg "What is water related to"

{
   "edges": {
      "e00": {
         "subject":   "n00",
         "object":    "n01",
         "predicates": ["biolink:related_to"]
      }
   },
   "nodes": {
      "n00": {
         "ids":        ["CHEBI:15377"]
      },
      "n01": {
         "categories":  ["biolink:Protein"]
      }
   }
}

takes about 4.6 min, of which 4min is devoted to overlaying NGD edges on nodes that will get filtered out of the block list.