Import an external skill into a registry

{  "imported": [    {      "ref": "string",      "version": "string",      "provenance": {        "sourceKind": "github",        "sourceUrl": "string",        "sourceRef": "string",        "upstreamHash": "string",        "importedAt": "2019-08-24T14:15:22Z"      },      "structuralWarnings": []    }  ],  "failed": []}

{  "defined": true,  "code": "UNAUTHORIZED",  "status": 401,  "message": "Authentication required or credentials invalid.",  "data": null}

{  "defined": true,  "code": "PLAN_LIMIT",  "status": 402,  "message": "This action exceeds your plan's limits.",  "data": {    "limit": "string",    "current": 0,    "max": 0,    "planId": "string",    "orgHandle": "string",    "suggestedPlanId": "string"  }}

{  "defined": true,  "code": "FORBIDDEN",  "status": 403,  "message": "You do not have permission to perform this action.",  "data": null}

{  "defined": true,  "code": "NOT_FOUND",  "status": 404,  "message": "The requested resource does not exist.",  "data": {    "resource": "string"  }}

{  "defined": true,  "code": "VALIDATION",  "status": 422,  "message": "The input failed domain validation.",  "data": {    "issues": [      {        "path": "string",        "message": "string"      }    ]  }}

{  "defined": true,  "code": "RATE_LIMITED",  "status": 429,  "message": "Rate limit exceeded; retry later.",  "data": {    "retryAfterSeconds": -9007199254740991  }}