CI: Refactor/Reorder *.star files (#52384)

* Refactor test pipelines

* Move pr, main and release starlark files under scripts/drone/event

* Move cron.star to scripts/drone/events

* Further unused code removal

* Introducing build.star

* Extract verify_drone.star

* Extract windows.star

* Extract publish.star

* Remove unused code

* Fix formatting in main.star

scripts/drone/steps/lib.star

@@ -1173,6 +1173,38 @@ def verify_gen_cue_step(edition):
         ],
     }
 
+def trigger_test_release():
+    return {
+        'name': 'trigger-test-release',
+        'image': build_image,
+        'environment': {
+            'GITHUB_TOKEN': from_secret('github_token'),
+            'DOWNSTREAM_REPO': from_secret('downstream'),
+            'TEST_TAG': 'v0.0.0-test',
+        },
+        'commands': [
+            'git clone "https://$${GITHUB_TOKEN}@github.com/grafana/grafana-enterprise.git" --depth=1',
+            'cd grafana-enterprise',
+            'git fetch origin "refs/tags/*:refs/tags/*"',
+            'git tag -d $${TEST_TAG} && git push --delete origin $${TEST_TAG} && git tag $${TEST_TAG} && git push origin $${TEST_TAG}',
+            'cd -',
+            'git fetch origin "refs/tags/*:refs/tags/*"',
+            'git remote add downstream https://$${GITHUB_TOKEN}@github.com/grafana/$${DOWNSTREAM_REPO}.git',
+            'git tag -d $${TEST_TAG} && git push --delete downstream --quiet $${TEST_TAG} && git tag $${TEST_TAG} && git push downstream $${TEST_TAG} --quiet',
+        ],
+        'failure': 'ignore',
+        'when': {
+            'paths': {
+                'include': [
+                    '.drone.yml',
+                ]
+            },
+            'repo': [
+                'grafana/grafana',
+            ]
+        }
+    }
+
 def artifacts_page_step():
     return {
         'name': 'artifacts-page',