Enable by default container-image collection (#983)

We want to enabled container-image collection by default. it will
be the case from agent 7.50.0. But in Operator 1.3.0, the Agent is
defaulted to 7.49.0 since 7.50.0 is not yet released.

This commit set the envvar DD_CONTAINER_IMAGE_ENABLED=true by default
in the NodeAgent's "agent" container.

apis/datadoghq/common/envvar.go

@@ -105,6 +105,7 @@ const (
 	DDRuntimeSecurityConfigNetworkEnabled             = "DD_RUNTIME_SECURITY_CONFIG_NETWORK_ENABLED"
 	DDRuntimeSecurityConfigActivityDumpEnabled        = "DD_RUNTIME_SECURITY_CONFIG_ACTIVITY_DUMP_ENABLED"
 	DDRuntimeSecurityConfigRemoteConfigurationEnabled = "DD_RUNTIME_SECURITY_CONFIG_REMOTE_CONFIGURATION_ENABLED"
+	DDContainerImageEnabled                           = "DD_CONTAINER_IMAGE_ENABLED"
 	DDSBOMEnabled                                     = "DD_SBOM_ENABLED"
 	DDSBOMContainerImageEnabled                       = "DD_SBOM_CONTAINER_IMAGE_ENABLED"
 	DDSBOMContainerImageAnalyzers                     = "DD_SBOM_CONTAINER_IMAGE_ANALYZERS"
@@ -136,4 +137,7 @@ const (
 	KubernetesEnvVar = "KUBERNETES"
 
 	ClusterChecksConfigProvider = "clusterchecks"
+
+	EnvVarTrueValue  = "true"
+	EnvVarFalseValue = "false"
 )

controllers/datadogagent/component/agent/default.go

@@ -268,7 +268,13 @@ func envVarsForCoreAgent(dda metav1.Object) []corev1.EnvVar {
 		},
 		{
 			Name:  apicommon.DDLeaderElection,
-			Value: "true",
+			Value: apicommon.EnvVarTrueValue,
+		},
+		{
+			// we want to default it in 7.49.0
+			// but in 7.50.0 it will be already defaulted in the agent process.
+			Name:  apicommon.DDContainerImageEnabled,
+			Value: apicommon.EnvVarTrueValue,
 		},
 	}