Create Custom Object

Creates a new custom object in an organization.
The key field is used to identify the custom object, it's written in snake case and it must be unique.
The label field can be used to give a human readable name to the custom object.
The custom_properties field is a list of custom properties that will be created with the custom object.
The custom_properties field is optional and properties can be added separately (one by one) via the custom property API.