Add podDisruptionBudget.enabled value

[Miouge1]

Is your feature request related to a problem? Please describe.
When draining a Kubernetes node with kubectl drain, several couchdb pods are sometimes evicted at the same time, resulting in an unavailable couchdb cluster.

Describe the solution you'd like
Adding a kind: PodDisruptionBudget option to allow for drain to respect the disruption budget. For example waiting for the first evicted pod to be ready before evicting the next one.

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Smaller kubernetes clusters are more affected by this since there are more chances that 2 couchdb pods are scheduled on the same node.

Here is an example of values that this could be controlled with:

podDisruptionBudget:
  enabled: false
  # minAvailable: 1
  maxUnavailable: 1

[clayvan]

Totally wild that nobody else has asked for this? Maybe everyone is just creating their own PDB for it like we are?