Add cosmos db complex properties

[JoasE]

Adds support for saving and retrieving complex properties and collections Adds support for querying complex properties

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        Summary of the changes
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        Fixes #bugnumber

• [x] Tests for the changes have been added (for bug fixes / features)
• [x] Code follows the same patterns and style as existing code in this repo

[JoasE]

TODO:

• [ ] Clean up and refactor (code duplication)
• [ ] Add JsonPropertyName method in modelbuilding for complex properties and use that for serialization (document source) and query compiling
• [ ] Investigate different behavior with discriminator
• [ ] Add serialization for update document (document source)