Introduce events in order to make it possible to see simple log message with...

Introduce events to display simple log message with kubectl describe execution

Looks like this:

Events:
  Type     Reason                        Age    From                 Message
  ----     ------                        ----   ----                 -------
  WARNING  Start experiment failed       5m22s  theodolite-operator  load: 25000, resources: 1
  WARNING  Stop experiment failed        5m21s  theodolite-operator  Teardown failed: Failed to create new KafkaAdminClient

At the moment events are created when an experiment is started or stopped or when the execution fails.

Closes #245 (closed)

theodolite/crd/crd-execution.yaml

@@ -51,7 +51,7 @@ spec:
                     description: The type of the resource. It must match one of the resource types specified in the referenced benchmark.
                     type: string
                   resourceValues:
-                    descriptoin:  List of resource values for the specified resource type.
+                    description:  List of resource values for the specified resource type.
                     type: array
                     items:
                       type: integer