Update the ontology related fields

[Ludee]

The newly added fields for the ontology reference were tested and need to be improved.

is_about

• [x] rename to isAbout
• [x] change value to a list

value_reference

• [x] rename to valueReference
• [x] change value to a nested list

subject

• [x] change value to a list

[Ludee]

The update was bigger than expected. I could extend the metadata to be able to link to the OEO. Main results are:

subject

    "subject": [
        {"name" : "energy",
        "path": "https://openenergy-platform.org/ontology/oeo/OEO_00000150"},
        {"name" : "test dataset",
        "path": "https://openenergy-platform.org/ontology/oeo/OEO_00000408"}
    ],

isAbout

    "isAbout": [
        {"name" : "wind farm",
        "path": "https://openenergy-platform.org/ontology/oeo/OEO_00000447"}
    ],

valueReference

    "valueReference": [
        {"value": "onshore ",
        "name": "onshore wind farm",
        "path" : "https://openenergy-platform.org/ontology/oeo/OEO_00000311"},
        {"value": "offshore ",
        "name": "offshore wind farm",
        "path" : "https://openenergy-platform.org/ontology/oeo/OEO_00000308"}
    ]

[steull]

Checked metadata key description and example file.