New commands for managing K8s cluster and repos

New options for vnf-show to show details of a kdu in a VNF instance
Use of textwrapper to wrap text of the prettytables for vnf-show,
ns-show, k8scluster-show, ns-list and vim-show
Updated trunc_text function to fix truncation to lenghth

Change-Id: I6f61533d6eff267d7858bb367e41e28dca8447ac
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>