volume-requested-topology annotation should be YAML string for better readability

[aruneshpa]

Is this a BUG REPORT or FEATURE REQUEST?:
/kind bug

What happened:
The current way to specify the list of zones where a volume would be available is to specify a JSON blob as a value of the volume-requested-topology annotation. While this works, this quickly becomes unreadable for any human interaction and consumption. A cleaner way would be to use YAML strings. Here a comparison of both current and the proposed approach:

Consider a scenario where a PVC is being made available in 5 zones (for illustration purpose). The value of the annotation starts to becomes unreadable.

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  annotations:
    csi.vsphere.volume-requested-topology: '[{"topology.kubernetes.io/zone":"zone-1"}, {"topology.kubernetes.io/zone":"zone-2"}, {"topology.kubernetes.io/zone":"zone-3"}, {"topology.kubernetes.io/zone":"zone-4"}, {"topology.kubernetes.io/zone":"zone-5"}]'

The same PVC will look like this using the proposed YAML string approach:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  annotations:
    csi.vsphere.volume-requested-topology: |
      - "topology.kubernetes.io/zone":"zone-1"
      - "topology.kubernetes.io/zone":"zone-2"
      - "topology.kubernetes.io/zone":"zone-3"
      - "topology.kubernetes.io/zone":"zone-4"
      - "topology.kubernetes.io/zone":"zone-5"

YAML as a string also has an advantage of being able to identify any mistakes while crafting the object (essential for non automation/machine users).

What you expected to happen:
N/A

How to reproduce it (as minimally and precisely as possible):
Create a multi zone PVC and observe the JSON blob in the annotation.

Anything else we need to know?:
N/A

Skipping the env section since this is present on main.

[aruneshpa]

cc @SandeepPissay , @akutz

[akutz]

Please note the use of the | character after the annotation key. This indicates a multi-line YAML string. I validated this works for annotations by creating a ConfigMap with one. Importantly the info is also returned in this format as well.