Add customizable securityContext

[xhejtman]

Description

While main components can set pod/container securityContext as needed, it is not settable for spawned statefulsets, where the security context is hardcoded and it is not sufficient for root-less environments.

Would it be possible to make it either settable or provide the rootless option where:

1. init container is ommited (cannot do chown without root anyway)
2. security context is set to:

securityContext: # Pod security context
  fsGroupChangePolicy: OnRootMismatch
  runAsNonRoot: true
  fsGroup: 1001 # this one will do the initcontainer job if the CSI driver is correctly configured
  seccompProfile:
    type: RuntimeDefault

and

securityContext: # Container security context
  runAsUser: 1001
  allowPrivilegeEscalation: false
  capabilities
    drop:
    - ALL