Refactor: Conform variable names to standardized vocabulary (pass#1)

[tokebe]

This PR is a first-pass attempt to address biothings/biothings_explorer/issues/379.

No actual behavior has been changed. Variable names have been changed to better reflect a set of standardized vocabulary for internal data structures (which should better reflect their purpose and relationship to external data structures).

Due to some data structures passed between modules, this PR requires biothings/bte_trapi_query_graph_handler/pull/93.

This PR will require additional review and discussion to ensure that there are no additional changes that should be made, etc.

[ariutta]

Looks good to me.

[colleenXu]

I don't see issues on this. I think the main discussion is in the other PR...

[colleenXu]

@tokebe I'm seeing one automated test that needs updating. The screenshot may be clearer

FAIL test/query.test.js
● Test query class › Test _merge function › logs is correctly populated

expect(received).toHaveProperty(path, value)

Expected path: "message"

Expected value: "call-apis: Total number of results returned for this query is 3"
Received value: "call-apis: Total number of records returned for this query is 3"

  86 |             caller._merge([success1, success2, success1, fail, fail]);
  87 |             expect(caller.logs).toHaveLength(1);
> 88 |             expect(caller.logs[0]).toHaveProperty("message", "call-apis: Total number of results returned for this query is 3")
     |                                    ^
  89 |         })
  90 |     })
  91 |

  at Object.<anonymous> (__test__/query.test.js:88:36)