Add User and Project IDs to entities

[toddroper]

We will need to determine how these data points are passed to the API. Our current proposal is to pass them through headers from the HMI to prevent updating every entity with the two identifiers.

• Discuss passing the two items with Uncharted.

[brandomr]

@dgauldie @YohannParis we'd talked about this before/during the hackathon. Perhaps we can revisit passing projects/user ids in the request headers instead of in the body of the requests?

[YohannParis]

Is this an issue because you are merging all fields on update? I can see how the hmi-server could add the user to the header, but a user might want to add a Model to several project at the same time in the future.