Add Tekton tasks, pipeline and test Dockerfile

- Add git-clone task for repository cloning
- Add kaniko-build task for container image builds
- Add container-build pipeline orchestrating clone + build
- Add harbor-credentials ExternalSecret for innoventions namespace
- Add test-app.Dockerfile for pipeline validation

Day 3 deliverables for Tekton Phase 2

cluster/platform/innoventions/harbor-credentials.yaml

@@ -0,0 +1,38 @@
+# ExternalSecret for Tekton robot account credentials
+# Syncs from 1Password item: harbor-robot-accounts
+# Creates a docker-registry type secret for Tekton pipeline authentication
+apiVersion: external-secrets.io/v1beta1
+kind: ExternalSecret
+metadata:
+  name: harbor-tekton-robot
+  namespace: innoventions
+spec:
+  refreshInterval: 1h
+  secretStoreRef:
+    name: onepassword-connect
+    kind: ClusterSecretStore
+  target:
+    name: harbor-credentials
+    creationPolicy: Owner
+    template:
+      type: kubernetes.io/dockerconfigjson
+      data:
+        .dockerconfigjson: |
+          {
+            "auths": {
+              "the-seas.local.mk-labs.cloud": {
+                "username": "{{ .tekton_username }}",
+                "password": "{{ .tekton_password }}",
+                "auth": "{{ printf "%s:%s" .tekton_username .tekton_password | b64enc }}"
+              }
+            }
+          }
+  data:
+    - secretKey: tekton_username
+      remoteRef:
+        key: harbor-robot-accounts
+        property: tekton-builder-username
+    - secretKey: tekton_password
+      remoteRef:
+        key: harbor-robot-accounts
+        property: tekton-builder-password