Adapt to new HealthECCO graph Datascheme

[motey]

Refactor proposals:

• Rename node label Start to double label Date:ClinicalTrialDate (we need to post process the date into a neo4j datetype later. thats why the extra label.)
• Add extra label Entity to Collaborator,Sponsor, Investigator and Contact (we will postproccess these through a organisation/person disambugation)
• rename label PaperId to ArticleId with property IdType=pudmed e.g. (:ArticleId {"ID": "25528508","IdType": "pubmed"}
• rename property word of label Keyword to Keyword e.g. (:Keyword {word:"ambulatory"}) becomes (:Keyword {Keyword:"ambulatory"})

Existing nodes in the new datamodel with possible connecitons to clinical trial loader:
City
exmaple:

(:City{
"geo": "Point(83.012777777 25.318888888)",
"wikidata_url": "http://www.wikidata.org/entity/Q79980",
"name": "Varanasi"})

Country
example:

(:Country{
"area": "652230",
"also_known_as": "AFG, af, 🇦🇫",
"ISO_3166_1_alpha_2_code": "AF",
"wikidata_url": "http://www.wikidata.org/entity/Q889",
"name": "Afghanistan",
"population": "37466414"
  })