contiv-vpp-bug-report.sh enhancements
contiv-vpp-bug-report.sh enhancements

Use 'kubectl exec' from the master instead of ssh where possible, to
handle the case where the machine running the script cannot ssh to
the k8s worker nodes.

For the STN logs (the only worker node log collection we can't use
kubectl exec for), use the node IP when we don't have a ssh config
file.

Don't stage log file collection on remote nodes, it only adds
additional complexity.  Instead, do log redirects on the local side.

Allow ssh connections to work without prompting to accept the host
key or resolve any host key conflicts.

Allow an external calling script to override the report directory
and tarball name.

Add ability to use a different ssh private key, without writing a
config file.

Use vppctl instead of netcat on the host, to handle the case where
netcat isn't installed.

Other general script cleanup to try and make things more consistent
and readable.

rastislavszabo/vpp,rastislavszabo/vpp,milanlenco/vpp-1,brecode/vpp,brecode/vpp,rastislavszabo/vpp,brecode/vpp,milanlenco/vpp-1,milanlenco/vpp-1,rastislavszabo/vpp,brecode/vpp,rastislavszabo/vpp,milanlenco/vpp-1,rastislavszabo/vpp,brecode/vpp,rastislavszabo/vpp,milanlenco/vpp-1