Feature Request: New CRD for DatadogWidget

[starlightromero]

Related to issue #2423

Problem

Even when the DatadogDashboard is able to use native yaml syntax instead of JSON string, a DatadogDashboard resource can balloon to hundreds or thousands of lines. This makes is hard to maintain.

Proposal

I propose a new CRD called DatadogWidget. This resource would look like the following:

apiVersion: datadoghq.com/v1alpha1
kind: DatadogWidget
metadata:
  name: example-widget
  namespace: monitoring
spec:
  definition:
    title: Pod Count
    type: query_value
    requests:
      - response_format: scalar
        queries:
          - data_source: metrics
            name: query1
            query: sum:kubernetes.pods.running{cluster_name:example-cluster,service:$app.value,env:$env.value}
            aggregator: last
    precision: 0

This resource would define 1 (and only one widget). Then this widget could be referenced in the DatadogDashboard resource.

widgetsRef:
  - name: example-widget
    namespace: monitoring
    layout:
      x: 0
      y: 0
      width: 2
      height: 2

This approach also allows widgets to be reusable across different dashboards. Users would still be able to use widgets together with widgetsRef