Add default value to core properties

[adecler]

Issues addressed by this PR

Closes #611

See issue for more details

[adecler]

@BHoMBot check required

[bhombot-ci]

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[pawelbaran]

Changes make sense, happy to approve 👍

[pawelbaran]

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[bhombot-ci]

@pawelbaran to confirm, the following actions are now queued:

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