feat: list images report stage number

Author: jimschubert

src/main/java/com/github/jimschubert/rewrite/docker/analysis/ListImages.java

@@ -57,7 +57,9 @@ public Docker.Document visitDocument(Docker.Document dockerfile, ExecutionContex
                 Path file = dockerfile.getSourcePath();
 
                 if (dockerfile.getStages() != null) {
-                    for (Docker.Stage stage : dockerfile.getStages()) {
+                    List<Docker.Stage> stages = dockerfile.getStages();
+                    for (int i = 0; i < stages.size(); i++) {
+                        Docker.Stage stage = stages.get(i);
                         if (stage != null) {
                             for (Docker child : stage.getChildren()) {
                                 if (child instanceof Docker.From) {
@@ -73,7 +75,8 @@ public Docker.Document visitDocument(Docker.Document dockerfile, ExecutionContex
                                             from.getTag(),
                                             from.getDigest(),
                                             platformSwitch,
-                                            from.getAlias().getText()
+                                            from.getAlias().getText(),
+                                            i
                                     ));
                                 }
                             }

src/main/java/com/github/jimschubert/rewrite/docker/table/ImageUseReport.java

@@ -54,5 +54,9 @@ public static class Row {
         @Column(displayName = "Image Alias",
                 description = "The alias of the image used in the Dockerfile.")
         String alias;
+
+        @Column(displayName = "Stage Number",
+                description = "The stage number of the image used in the Dockerfile.")
+        Integer stageNumber;
     }
 }

src/test/java/com/github/jimschubert/rewrite/docker/analysis/ListImagesTest.java

@@ -30,11 +30,11 @@ void listImages() {
                         .typeValidationOptions(TypeValidation.builder().immutableScanning(false).build())
                         .dataTableAsCsv(ImageUseReport.class,
                         """
-                        path,image,tag,digest,platform,alias
-                        Dockerfile,alpine,latest,,,
-                        old.dockerfile,alpine,latest,,,build
-                        nested/Dockerfile,alpine,latest,,linux/amd64,build
-                        nested/Dockerfile,debian,latest,,,
+                        path,image,tag,digest,platform,alias,stageNumber
+                        Dockerfile,alpine,latest,,,,0
+                        old.dockerfile,alpine,latest,,,build,0
+                        nested/Dockerfile,alpine,latest,,linux/amd64,build,0
+                        nested/Dockerfile,debian,latest,,,,1
                         """),
                 dockerfile(
                         "FROM alpine:latest",