Add support for operations

[negz]

Description of your changes

I want to get this working to test crossplane/docs#956.

Tested with crossplane/crossplane#6695:

$ crossplane alpha render op example/operation/operation.yaml example/operation/functions.yaml --required-resources example/operation/ingress.yaml -r
---
apiVersion: ops.crossplane.io/v1alpha1
kind: Operation
metadata:
  creationTimestamp: null
  name: check-cert-expiry
status:
  appliedResourceRefs:
  - apiVersion: networking.k8s.io/v1
    kind: Ingress
    name: example-ingress
    namespace: default
  pipeline:
  - output:
      certificateExpires: Sep 29 08:34:02 2025 GMT
      daysUntilExpiry: 53
      hostname: google.com
      status: ok
    step: check-certificate
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  annotations:
    cert-monitor.crossplane.io/days-until-expiry: "53"
    cert-monitor.crossplane.io/expires: Sep 29 08:34:02 2025 GMT
    cert-monitor.crossplane.io/status: ok
  name: example-ingress
  namespace: default

I have:

• Read and followed Crossplane's contribution process.
• Added or updated unit tests for my change.