phase 3: add qualifier info from TRAPI KPs to general-ARA /meta_knowledge_graph response

[colleenXu]

From bullet 4 of the changelog:

In MetaKnowledgeGraph component, added MetaEdge.qualifiers as list of new MetaQualifier types https://github.com/NCATSTranslator/ReasonerAPI/pull/387/files

With TRAPI 1.4, tools can specify qualifiers in their /meta_knowledge_graph endpoint responses (edges section). We probably want to use this format to advertise the qualifier info we get from the TRAPI KPs we ingest. This only affects the general-ARA endpoint (v1/meta_knowledge_graph).

• timing: after the issue on ingesting qualifier info from TRAPI KPs we use
• priority: medium (relative to other phase 3 issues)

Other notes:

• Maybe relevant: older discussion of our /meta_knowledge_graph endpoints and qualifier info: here and reply

[colleenXu]

Restating some info from above: this issue is probably on-hold because it (1) depends on the issue 597 (already linked), (2) is affected by the "qualifier-set merging" discussion, and (3) probably won't be used by anyone

[tokebe]

Assigning to @rjawesome if he has time.

[rjawesome]

See #628 and biothings/smartapi-kg.js#77 (Also fixes the issue on the PRs which would add trapi qualifiers to be used in query filtering). I am keeping this in the same PRs with the other TRAPI qualifier issue because they both use the same code to check TRAPI metakg responses for qualifiers.

[tokebe]

Oh, I had missed that this functionality was added by those PRs - awesome, thanks!