[Feature/Operator] Support shareProcessNamespace feature

[juldrixx]

From nifikop created by erdrix: Orange-OpenSource/nifikop#2

Feature Request

Is your feature request related to a problem? Please describe.

If we want to be able to debug operator or cluster's nodes, we need to use kubectl alpha debug command with ephemeral containers instead of kubectl exec. To do so, we need to enable shareProcessNamespace into pods.

Describe the solution you'd like to see

Add this field into the CRD and in chart template.

Additional context

Check with security team if there are any restrictions about letting it enabled !

[mh013370]

One option might be to create a kubectl krew plugin to contain all of the utilities needed to quickly inspect and change NiFi cluster deployments.

Initially, i had thought we could create a companion nifikop toolbox deployment (similar to how rook-ceph toolbox works) that is always running with the kubectl plugin pre-installed. But it appears that a krew plugin would be sufficient.