[FIXED JENKINS-18485] Use correct node permissions in remote API

From now on user needs:
  Computer.CREATE to use 'create-node' CLI command
  Computer.DELETE to use 'delete-node' CLI command
  Computer.CONFIGURE to use 'update-node' CLI command and its REST alternative
  Computer.READ to use 'get-node' CLI command and its REST alternative

https://issues.jenkins-ci.org/browse/JENKINS-18485