Create a new persona.
Create a new persona for the FolksDummy.PersonaStore store, with 
            the given construct-only properties.
The persona’s Folks.Persona.writeable_properties are initialised to the given store
            ’s Folks.PersonaStore.always_writeable_properties. They may be updated afterwards using 
            FolksDummy.Persona.update_writeable_properties.
| store | the store which will contain the persona | 
| contact_id | a unique free-form string identifier for the persona | 
| is_user | 
 | 
| linkable_properties | an array of names of the properties which should be used for linking this persona to others | 
0.9.7