client_connect_permission_endpoint Add client connect permission endpoin...

Add an endpoint for client connect permissions. 
If we have the association `contact` and `user` then the `user_id` and `contact_id` fields are autogenerated for us. 

Further, Marc just added an additional field: https://github.com/clio/themis/commit/9f755a8046d56319a9dee4c160b894d66db4f5e8 
Can you update it.