Enable content.get() to support the same optional params as GET /v1/content/{guid}

[cgraham-rs]

As an SDK user,
I want the content.get(guid) function to support the same optional parameters as the Connect API endpoint GET /v1/content/{guid},
so that I can access the full range of content metadata and behavior available through the API directly from the SDK.

tags: Populates a tags field for the returned content item containing the tags associated with this content item.
owner: Populates an owner field for the returned content item with basic details about the content owner.
vanitiy_url: Populates the vanity_url field for the returned content item if the content has an associated custom vanity URL.