Add Helm template annotations

[novotl]

Current behavior

Prefect-server Helm chart doesn't support this currently. What exists is metadata.annotations which is not what I have in mind. I need to pass the annotations to the Pod.

Proposed behavior

Make it possible to add spec.template.metadata.annotations, the motivations behind this is:

• adding datadog annotations to configure log collection
• adding vault annotations to inject secrets (PGPASSWORD) from vault
• ...

Example

For example adding Datadog log configuration using autodiscovery (snippet from here)

apiVersion: v1
kind: Pod
# (...)
metadata:
  name: '<POD_NAME>'
  annotations:
    ad.datadoghq.com/<CONTAINER_IDENTIFIER>.logs: '[<LOG_CONFIG>]'
    # (...)
spec:
  containers:
    - name: '<CONTAINER_IDENTIFIER>'
# (...)

requires following Deployment configuration:

apiVersion: apps/v1
kind: Deployment
# (...)
spec:
  template:
    metadata:
      annotations: # <- this is currently not possible to add
        ad.datadoghq.com/<CONTAINER_IDENTIFIER>.logs: '[<LOG_CONFIG>]'
# (...)