feat(scheduler): Add tracing support

[thisthat]

A single Span is created for the whole scheduling until the Pod is binded to a node. Status changes are reported as events.

		"SpanContext": {
			"TraceID": "44382924dc4e184bf358336002c8ebbe",
			"SpanID": "8eb9ca277492f955",
			"TraceFlags": "01",
			"TraceState": null,
			"Remote": false
		},
		"Parent": {
			"TraceID": "44382924dc4e184bf358336002c8ebbe",
			"SpanID": "029961c2f06e15c8",
			"TraceFlags": "01",
			"TraceState": null,
			"Remote": true
		},
		"SpanKind": 1,
		"Name": "schedule",
		"StartTime": "2022-10-06T17:33:06.220931583Z",
		"EndTime": "2022-10-06T17:33:37.811943595Z",
		"Attributes": [
			{
				"Key": "keptn.deployment.app_name",
				"Value": {
					"Type": "STRING",
					"Value": "waiter"
				}
			},
			{
				"Key": "keptn.deployment.workload",
				"Value": {
					"Type": "STRING",
					"Value": "waiter-waiter"
				}
			},
			{
				"Key": "keptn.deployment.version",
				"Value": {
					"Type": "STRING",
					"Value": "0.2"
				}
			},
			{
				"Key": "keptn.deployment.namespace",
				"Value": {
					"Type": "STRING",
					"Value": "default"
				}
			}
		],
		"MessageEvents": [
			{
				"Name": "StatusEvaluation",
				"Attributes": [
					{
						"Key": "keptn.deployment.status",
						"Value": {
							"Type": "STRING",
							"Value": "Succeeded"
						}
					}
				],
				"DroppedAttributeCount": 0,
				"Time": "2022-10-06T17:33:37.811941482Z"
			}
		],
		"Links": null,
		"StatusCode": "Unset",
		"StatusMessage": "",
		"DroppedAttributeCount": 0,
		"DroppedMessageEventCount": 0,
		"DroppedLinkCount": 0,
		"ChildSpanCount": 0,
		"Resource": [
			{
				"Key": "service.name",
				"Value": {
					"Type": "STRING",
					"Value": "unknown_service:kube-scheduler"
				}
			},
			{
				"Key": "telemetry.sdk.language",
				"Value": {
					"Type": "STRING",
					"Value": "go"
				}
			},
			{
				"Key": "telemetry.sdk.name",
				"Value": {
					"Type": "STRING",
					"Value": "opentelemetry"
				}
			},
			{
				"Key": "telemetry.sdk.version",
				"Value": {
					"Type": "STRING",
					"Value": "0.20.0"
				}
			}
		],
		"InstrumentationLibrary": {
			"Name": "keptn/scheduler",
			"Version": ""
		}
	}

Solves #96

[thschue]

lgtm