Feature 10908: Update charm in running VNF instance

Adding robot test Basic 25
This test instantiates NS, updates the VNFD, update the VNF instance
by upgrading charm. Then it executes the new added action on this VNF.

Change-Id: I68140f01fadf791a512870ff0f6b0babfcb67e0c
Signed-off-by: aticig <gulsum.atici@canonical.com>