Make odo build-images return an error if no Image component found

As reported in redhat-developer#5330, this makes more sense rather than exiting silently.

pkg/devfile/image/image.go

@@ -9,6 +9,7 @@ import (
 	devfile "github.com/devfile/api/v2/pkg/apis/workspaces/v1alpha2"
 	"github.com/devfile/library/pkg/devfile/parser"
 	"github.com/devfile/library/pkg/devfile/parser/data/v2/common"
+	"github.com/redhat-developer/odo/pkg/libdevfile"
 	"github.com/redhat-developer/odo/pkg/log"
 )
 
@@ -39,6 +40,9 @@ func BuildPushImages(devfileObj parser.DevfileObj, path string, push bool) error
 	if err != nil {
 		return err
 	}
+	if len(components) == 0 {
+		return libdevfile.NewComponentTypeNotFoundError(devfile.ImageComponentType)
+	}
 
 	for _, component := range components {
 		err = buildPushImage(backend, component.Image, path, push)

pkg/libdevfile/errors.go

@@ -83,3 +83,18 @@ func NewNotAContainerError() NotAContainerError {
 func (e NotAContainerError) Error() string {
 	return "component not a container"
 }
+
+// ComponentTypeNotFoundError is returned when no component with the specified type has been found in Devfile
+type ComponentTypeNotFoundError struct {
+	componentType v1alpha2.ComponentType
+}
+
+func NewComponentTypeNotFoundError(componentType v1alpha2.ComponentType) ComponentTypeNotFoundError {
+	return ComponentTypeNotFoundError{
+		componentType: componentType,
+	}
+}
+
+func (e ComponentTypeNotFoundError) Error() string {
+	return fmt.Sprintf("no component with type %q found in Devfile", e.componentType)
+}