Send MetaKG to threads

[rjawesome]

This creates a MetaKG during the cron job and saves the operations. It then sends the operations to each thread. This allows the time to create MetaKG to go from around 500ms to 1ms.
This also writes smartapi specs to redis, so they can be used in query graph handler for finding unregistered APIs (prevents read-write conflicts).

[tokebe]

@rjawesome Please re-review related PRs and fix with new merge conflicts -- I'll review and merge once you have.

[colleenXu]

It may be helpful to link this/related PRs to the issue that they address?

[tokebe]

@colleenXu Implementation covers performance improvements not currently in an issue, as well as addressing biothings/biothings_explorer#703

[rjawesome]

All Associated PRs should be fixed
biothings/biothings_explorer#814 (new)
biothings/bte_trapi_query_graph_handler#183
biothings/smartapi-kg.js#87

[tokebe]

@rjawesome Just about ready to merge, the only thing I'm a bit confused about is the new data/kg.json file. It doesn't appear to be used in related PRs? Am I mistaken, or should it be removed?

[rjawesome]

You are correct about kg/data.json (it's removed). I also changed it so the specs would be passed through the thread (similar to MetaKG) instead of through redis.