feat: reconcile AccessKey

[tenstad]

Appears only Observe can write to Status. Using external name to transport from Create to Observe: https://github.com/crossplane-contrib/provider-aws/blob/2a9ac2c9815c3a92aff575f2c879c40193287280/pkg/controller/iam/accesskey/controller.go#L165

---
apiVersion: user.cloudian.crossplane.io/v1alpha1
kind: AccessKey
metadata:
    name: tenant1-user2
spec:
    forProvider:
        groupId: tenant1
        userId: user2
    writeConnectionSecretToRef:
        namespace: default
        name: s3creds
status:
    atProvider:
        accessKey: 57927689798c12cafa5c
---
apiVersion: v1
kind: Secret
metadata:
  name: s3creds
  namespace: default
data:
  secretKey: QmJVTDFWbDk1ZTJnWGo4dCsxOHBuSTZueWh6cVFXTlcvWnFrSFlvLw==

Thinking to extend to selector and ref in the future, as with https://marketplace.upbound.io/providers/upbound/provider-aws-iam/v1.18.3/resources/iam.aws.upbound.io/AccessKey/v1beta1