feat: add optional logging for expander stages

[xiaoweim]

This PR adds the option to enable logging for each expander stage for better debug ability.

Log message start with expanderDebugLog---${Kind}/${Namespace}/${Name}---version: ${Version}

Example log:

2024-06-29T00:35:34Z	DEBUG	events	expanderDebugLog---PConfig/team-a/team-a-config---version: 1	{"type": "Normal", "object": {"kind":"PConfig","namespace":"team-a","name":"team-a-config","uid":"9d674656-1db3-4d54-b5eb-f51bf90d8732","apiVersion":"facade.foocorp.com/v1alpha1","resourceVersion":"679"}, "reason": "Running expander stage 0: common"}

2024-06-29T00:35:34Z	DEBUG	events	expanderDebugLog---PConfig/team-a/team-a-config---version: 1---request: config:"apiVersion: v1\nkind: ConfigMap\nmetadata:\n  name: common-config\n  namespace: {{ pconfigs.metadata.namespace }}\n  labels:\n    createdby: \"composition-namespaceconfigmap\"\ndata:\n  key1: value1" context:"{\"apiVersion\":\"composition.google.com/v1alpha1\",\"kind\":\"Context\",\"metadata\":{\"creationTimestamp\":\"2024-06-29T00:35:33Z\",\"generation\":1,\"managedFields\":[{\"apiVersion\":\"composition.google.com/v1alpha1\",\"fieldsType\":\"FieldsV1\",\"fieldsV1\":{\"f:spec\":{\".\":{},\"f:project\":{}}},\"manager\":\"testcases.test\",\"operation\":\"Update\",\"time\":\"2024-06-29T00:35:33Z\"}],\"name\":\"context\",\"namespace\":\"team-a\",\"resourceVersion\":\"678\",\"uid\":\"aafd1a60-c07c-4d2e-95e7-059be18ef8b9\"},\"spec\":{\"project\":\"proj-a\"}}" facade:"{\"apiVersion\":\"facade.foocorp.com/v1alpha1\",\"kind\":\"PConfig\",\"metadata\":{\"annotations\":{\"composition-expander-debug-logs\":\"true\"},\"creationTimestamp\":\"2024-06-29T00:35:33Z\",\"generation\":1,\"managedFields\":[{\"apiVersion\":\"facade.foocorp.com/v1alpha1\",\"fieldsType\":\"FieldsV1\",\"fieldsV1\":{\"f:metadata\":{\"f:annotations\":{\".\":{},\"f:composition-expander-debug-logs\":{}}},\"f:spec\":{\".\":{},\"f:project\":{}}},\"manager\":\"testcases.test\",\"operation\":\"Update\",\"time\":\"2024-06-29T00:35:33Z\"}],\"name\":\"team-a-config\",\"namespace\":\"team-a\",\"resourceVersion\":\"679\",\"uid\":\"9d674656-1db3-4d54-b5eb-f51bf90d8732\"},\"spec\":{\"project\":\"proj-a\"}}" value:"{}" resource:"pconfigs", result: error:{} type:MANIFESTS manifests:"apiVersion: v1\nkind: ConfigMap\nmetadata:\n  name: common-config\n  namespace: team-a\n  labels:\n    createdby: \"composition-namespaceconfigmap\"\ndata:\n  key1: value1"	{"type": "Normal", "object": {"kind":"PConfig","namespace":"team-a","name":"team-a-config","uid":"9d674656-1db3-4d54-b5eb-f51bf90d8732","apiVersion":"facade.foocorp.com/v1alpha1","resourceVersion":"679"}, "reason": "Expander stage common evaluation completed"}

2024-06-29T01:02:23Z	DEBUG	events	expanderDebugLog---PConfig/team-a/team-a-config---version: 1---resource count: 1	{"type": "Normal", "object": {"kind":"PConfig","namespace":"team-a","name":"team-a-config","uid":"431e53bf-1c9c-4ee2-873d-bdf4028c98db","apiVersion":"facade.foocorp.com/v1alpha1","resourceVersion":"678"}, "reason": "Finished expander stage 0: common"}

[xiaoweim]

/assign @barney-s @cheftako

[barney-s]

/approve
/lgtm

[barney-s]

Not sure if there is a limit on what can be sent to an event. Nevertheless lets try it.

[google-oss-prow]

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This pull-request has been approved by: barney-s

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