Consolidate document id field

[jupe]

Status

READY

Migrations

NO

Description

Testcase and Resource models has conversion for _id field and in API there was visible id. This PR consolidate id handling so that its same for each models - just mongo default _id.
-> Rename testcase and resource identify field: id -> _id that was done in toJSON transformer.

NOTE:

• This is breaking change - resource and test case identified field is changed from id -> _id.
• Does not affect opentmi-pyclient neither opentmi-jsclient because they expects already that _id field exists in these documents.

Todos

• Tests

[coveralls]

Coverage increased (+0.4%) to 71.813% when pulling 4e2e0a7 on resource._id into 4203b0f on master.

[coveralls]

Coverage increased (+0.4%) to 71.813% when pulling f4d332d on resource._id into 4203b0f on master.

[coveralls]

Coverage increased (+0.4%) to 71.813% when pulling f4d332d on resource._id into 4203b0f on master.

[coveralls]

Coverage increased (+0.4%) to 71.813% when pulling f4d332d on resource._id into 4203b0f on master.