[bitnami/grafana-operator] Add some pod scheduling directives

[dazoakley]

Description of the change

This adds the ability to set some pod scheduling primitives on the created grafana instance (if required):

• topologySpreadConstraints on the created grafana deployment/pods
• A PodDisruptionBudget resource targeted at the created grafana instance to add resiliency

Benefits

This will allow users to improve the scheduling of their pods (i.e. across AZs) and also ensure resiliency in node recycling events.

Possible drawbacks

This assumes users are not setting a component label on their operator deployment. This would be an easy change for any consumer though (to remove/update their label)

Applicable issues

n/a

Additional information

n/a

Checklist

• Chart version bumped in Chart.yaml according to semver. This is not necessary when the changes only affect README.md files.
• Variables are documented in the values.yaml and added to the README.md using readme-generator-for-helm
• Title of the pull request follows this pattern [bitnami/<name_of_the_chart>] Descriptive title
• All commits signed off and in agreement of Developer Certificate of Origin (DCO)

[andresbono]

LGTM. Thank you for your contribution!! 🎉