Emit events during reconcile runs

[bmarinov]

Is your feature request related to a problem? Please describe.
Events for state transitions and terminal errors are missing.

Describe the solution you'd like
A small set of events, covering only the aspects relevant to platform or ops teams (alerting). A few Normal events whenever external changes are made.

[bmarinov]

Already covered:

• BucketCreated (Normal): bucket created in Garage
• BucketCreateFailed (Warning): Garage create failed
• ConfigMapAccessForbidden (Warning): RBAC denial in tenant namespace (Bucket)
• SecretAccessForbidden (Warning): RBAC denial: covers regular reconcile with AccessKey as well as existing bucket