Task: /Bug: Gracefully handle Azure Delete on MySqlServer

[melonrush13]

When I delete a MySqlServer instance on the Azure portal, the operator doesn't register that delete and throws an error with code OperationIdNotFound

2020-05-08T09:14:30.533-0600    ERROR    controller-runtime.controller    Reconciler error    {"controller": "mysqlserver", "request": "default/aso-wpdemo-mysqlserver", "error": "1 error occurred:\n\t* sql.PollClient#Get: Failure responding to request: StatusCode=404 -- Original Error: autorest/azure: Service returned an error. Status=404 Code=\"OperationIdNotFound\" Message=\"The operation with Id: '1dfe0027-356f-461a-af64-d4a81df4fcd5' does not exist.\"\n\n"}
github.com/go-logr/zapr.(*zapLogger).Error
    /Users/melanierush/go/pkg/mod/github.com/go-logr/zapr@v0.1.0/zapr.go:128
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).reconcileHandler
    /Users/melanierush/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.5.0/pkg/internal/controller/controller.go:258
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).processNextWorkItem
    /Users/melanierush/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.5.0/pkg/internal/controller/controller.go:232
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).worker
    /Users/melanierush/go/pkg/mod/sigs.k8s.io/controller-runtime@v0.5.0/pkg/internal/controller/controller.go:211
k8s.io/apimachinery/pkg/util/wait.JitterUntil.func1
    /Users/melanierush/go/pkg/mod/k8s.io/apimachinery@v0.17.2/pkg/util/wait/wait.go:152
k8s.io/apimachinery/pkg/util/wait.JitterUntil
    /Users/melanierush/go/pkg/mod/k8s.io/apimachinery@v0.17.2/pkg/util/wait/wait.go:153
k8s.io/apimachinery/pkg/util/wait.Until
    /Users/melanierush/go/pkg/mod/k8s.io/apimachinery@v0.17.2/pkg/util/wait/wait.go:88
2020-05-08T09:14:40.776-0600    INFO    controllers.MySQLServer    setting parent reference    {"Info Ty

To Re Create

• Create a MySqlServer using the operator
• Verify existence on operator and Azure
• Delete the server using the Azure portal
• Observe the output from the reconciler - should see zapper err from above with continuous reconciliation

Done criteria
Gracefully handle a delete from Azure side and reflect it on the operator side.

• For eg. After this task is done, the user should be able to use either webhooks or the declarative model for K8s

User story reference

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