[DataFactory] Adding additionalProperties to roundtrip new properties

[hvermis]

Description

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Adding additionalProperties to some of the types to support round-tripping new properties to the service. The PR also contains changes from other people that were not merged yet. Those are the new sources for Copy activity.

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[hvermis]

Swagger PR:
Azure/azure-rest-api-specs#2033

[hvermis]

I have tried testing it local private version of ClientRuntime. While the deserialization worked for additional properties - new property made it to the AdditionProperties with its name as key and value as value, but it did not get serialized back into json. It could be either because of serialization settings or there is another bug in ClientRuntime. Will follow up with the Azure SDK dev team.

[hvermis]

Will create new as I had merge problems