[manila-csi-plugin] allow podSecurityContexts to be set in controllerplugin and nodeplugin

[xrisaD]

/kind feature

What happened:

Allow the pod-level security contexts to be configurable via helm values.yaml for manila-csi-plugin for both the controllerplugin and nodeplugin.

What you expected to happen:
Proposed solution would be something along the lines of the below: with a default of no securityContext set to prevent breaking changes in end user. This allows for the flexibility to specify any of the podSecurityContext options.

# values.yaml
controllerplugin:
  podSecurityContext: {}

nodeplugin:
  podSecurityContext: {}

---
# charts/manila-csi-plugin/templates/controllerplugin-statefulset.yaml
kind: StatefulSet
apiVersion: apps/v1
...
  template:
    metadata:
    spec:
     securityContext: {{ toYaml .Values.nodeplugin.podSecurityContext | nindent 8 }}
...

---
# charts/manila-csi-plugin/templates/nodeplugin-daemonset.yaml
kind: DaemonSet
apiVersion: apps/v1
...
 template:
    metadata:
    spec:
     securityContext: {{ toYaml .Values.nodeplugin.podSecurityContext | nindent 8 }}
...

How to reproduce it:
n/a

Anything else we need to know?:
n/a

Environment:

• openstack-cloud-controller-manager(or other related binary) version:
• OpenStack version:
• Others: