Add ConfRef conferences as a lookup source

[WolfgangFahl]

Get data from http://portal.confref.org/ via the api at

# get sample data from confref http://portal.confref.org/api
#
getConfRef() {
for entity in countries areas conferences
do
  target=$sampledir/confref-$entity.json
  src=http://portal.confref.org/api/$entity/ 
  download $src $target
done
}```

Examples:

```{
    "id": "btw2021",
    "name": "Datenbanksysteme für Business, Technologie und Web Datenbanksysteme in Büro, Technik und Wissenschaft",
    "acronym": "BTW",
    "country": "Germany",
    "city": "Dresden",
    "year": 2021,
    "startDate": "2021-01-01",
    "endDate": "2021-01-01",
    "description": null,
    "shortDescription": null,
    "address": null,
    "submissionDate": null,
    "notificationDate": null,
    "submissionExtended": false,
    "cameraReadyDate": null,
    "confSeries": {
      "id": "btw",
      "issn": null,
      "eissn": null,
      "dblpId": "https://dblp.org/db/conf/btw/",
      "name": "Datenbanksysteme für Business, Technologie und Web Datenbanksysteme in Büro, Technik und Wissenschaft",
      "description": null
    },
    "area": {
      "value": "Computer Science",
      "id": 2
    },
    "keywords": [],
    "ranks": []
  },
  {
    "id": "scdm2020",
    "name": "International Conference on Soft Computing and Data Mining",
    "acronym": "SCDM",
    "country": "Malaysia",
    "city": "Langkawi",
    "year": 2020,
    "startDate": "2020-01-22",
    "endDate": "2020-01-23",
    "description": null,
    "shortDescription": null,
    "address": null,
    "submissionDate": null,
    "notificationDate": null,
    "submissionExtended": false,
    "cameraReadyDate": null,
    "confSeries": {
      "id": "scdm",
      "issn": null,
      "eissn": null,
      "dblpId": "https://dblp.org/db/conf/scdm/",
      "name": "Soft Computing and Data Mining",
      "description": null
    },
    "area": {
      "value": "Computer Science",
      "id": 2
    },
    "keywords": [
      "Data mining",
      "Machine learning",
      "Deep learning",
      "Convolutional neural network",
      "Classification",
      "Android",
      "Artificial neural network",
      "Sentiment analysis",
      "Deep neural network",
      "Performance",
      "Autoencoder",
      "Advertisement",
      "Analytical Hierarchy Process (AHP)",
      "NeuCube",
      "ASEAN",
      "Agile software development (ASD)",
      "Android botnet",
      "Ant lion optimizer",
      "Arabic datasets",
      "Area: system development"
    ],
    "ranks": []
  },
  {
    "id": "swqd2020",
    "name": "International Conference on Software Quality",
    "acronym": "SWQD",
    "country": "Austria",
    "city": "Vienna",
    "year": 2020,
    "startDate": "2020-01-14",
    "endDate": "2020-01-17",
    "description": null,
    "shortDescription": null,
    "address": null,
    "submissionDate": null,
    "notificationDate": null,
    "submissionExtended": false,
    "cameraReadyDate": null,
    "confSeries": {
      "id": "swqd",
      "issn": null,
      "eissn": null,
      "dblpId": "swqd",
      "name": "International Conference on Software Quality",
      "description": null
    },
    "area": {
      "value": "Computer Science",
      "id": 2
    },
    "keywords": [
      "Machine learning",
      "Risk",
      "Optimisation",
      "requirements engineering",
      "economics",
      "Mapping study",
      "quality assurance",
      "Data-intensive",
      "Big Data testing",
      "Code reviews",
      "Code walkthroughs",
      "Competency satisfaction levels",
      "Essential competencies",
      "Exploratory survey",
      "Industry academia collaboration",
      "Regression Risk Coverage",
      "Regression test",
      "Similarity detection",
      "Soft competency",
      "Software engineers’ competencies"
    ],
    "ranks": []
  },
  {
    "id": "i4cs2020",
    "name": "International Conference on Innovations for Community Services",
    "acronym": "I4CS",
    "country": "India",
    "city": "Bhubaneswar",
    "year": 2020,
    "startDate": "2020-01-12",
    "endDate": "2020-01-14",
    "description": null,
    "shortDescription": null,
    "address": null,
    "submissionDate": null,
    "notificationDate": null,
    "submissionExtended": false,
    "cameraReadyDate": null,
    "confSeries": {
      "id": "i4cs",
      "issn": null,
      "eissn": null,
      "dblpId": null,
      "name": "International Conference on Innovations for Community Services",
      "description": null
    },
    "area": {
      "value": "Computer Science",
      "id": 2
    },
    "keywords": [
      "Community detection",
      "Social network",
      "6LoWPAN",
      "Adaptive",
      "Internet of Things (IoT)",
      "Computational intelligence",
      "Centrality",
      "Cognitive Radio",
      "Collaborative platform",
      "Customer Experience",
      "Blind computing",
      "blacklisting",
      "Batch auditing",
      "Added-content analysis",
      "Buffer reservation attack",
      "Carrier selection",
      "Community service",
      "Contract optimization",
      "CRM telecommunication",
      "Customer data dashboard"
    ],
    "ranks": []
  },```