cloudapi: implement GCP target results and include UploadOptions

Return GCP-specific target results form the worker, similar as it is
done for AWS.

Extend Cloud API to allow GCP-specific upload Options.

Modify Cloud API to return UploadOptions as part of the UploadStatus.

Modify Cloud API integration test to check returned upload Options and
upload Type.

Signed-off-by: Tomas Hozza <thozza@redhat.com>

internal/target/gcp_target.go

@@ -14,3 +14,14 @@ func (GCPTargetOptions) isTargetOptions() {}
 func NewGCPTarget(options *GCPTargetOptions) *Target {
 	return newTarget("org.osbuild.gcp", options)
 }
+
+type GCPTargetResultOptions struct {
+	ImageName string `json:"image_name"`
+	ProjectID string `json:"project_id"`
+}
+
+func (GCPTargetResultOptions) isTargetResultOptions() {}
+
+func NewGCPTargetResult(options *GCPTargetResultOptions) *TargetResult {
+	return newTargetResult("org.osbuild.gcp", options)
+}

internal/target/targetresult.go

@@ -47,6 +47,8 @@ func UnmarshalTargetResultOptions(trName string, rawOptions json.RawMessage) (Ta
 	switch trName {
 	case "org.osbuild.aws":
 		options = new(AWSTargetResultOptions)
+	case "org.osbuild.gcp":
+		options = new(GCPTargetResultOptions)
 	default:
 		return nil, fmt.Errorf("Unexpected target result name: %s", trName)
 	}