CI: Make build, test and integration tests steps run in parallel (#40794)

* Make build and test steps run in parallel

* Make tests and builds run on different pipelines

* Make test-backend depend on initialize

* Rename

* Create standalone integration tests pipeline (#41730)

* Remove unused variables

scripts/drone/steps/lib.star

@@ -124,7 +124,7 @@ def initialize_step(edition, platform, ver_mode, is_downstream=False, install_de
 
     return steps
 
-def download_grabpl():
+def download_grabpl_step():
     return {
         'name': 'grabpl',
         'image': curl_image,
@@ -312,7 +312,7 @@ def build_backend_step(edition, ver_mode, variants=None, is_downstream=False):
         'name': 'build-backend' + enterprise2_suffix(edition),
         'image': build_image,
         'depends_on': [
-            'test-backend' + enterprise2_suffix(edition),
+            'initialize',
         ],
         'environment': env,
         'commands': cmds,
@@ -345,7 +345,7 @@ def build_frontend_step(edition, ver_mode, is_downstream=False):
         'name': 'build-frontend',
         'image': build_image,
         'depends_on': [
-            'test-frontend',
+            'initialize',
         ],
         'commands': cmds,
     }
@@ -375,7 +375,7 @@ def build_plugins_step(edition, sign=False):
         'name': 'build-plugins',
         'image': build_image,
         'depends_on': [
-            'lint-backend',
+            'initialize',
         ],
         'environment': env,
         'commands': [
@@ -389,7 +389,7 @@ def test_backend_step(edition):
         'name': 'test-backend' + enterprise2_suffix(edition),
         'image': build_image,
         'depends_on': [
-            'lint-backend',
+            'initialize',
         ],
         'commands': [
             './bin/grabpl test-backend --edition {}'.format(edition),
@@ -401,7 +401,7 @@ def test_backend_integration_step(edition):
         'name': 'test-backend-integration' + enterprise2_suffix(edition),
         'image': build_image,
         'depends_on': [
-            'lint-backend',
+            'initialize',
         ],
         'commands': [
             './bin/grabpl integration-tests --edition {}'.format(edition),
@@ -688,7 +688,7 @@ def postgres_integration_tests_step():
         'name': 'postgres-integration-tests',
         'image': build_image,
         'depends_on': [
-            'initialize',
+            'grabpl',
         ],
         'environment': {
             'PGPASSWORD': 'grafanatest',
@@ -712,7 +712,7 @@ def mysql_integration_tests_step():
         'name': 'mysql-integration-tests',
         'image': build_image,
         'depends_on': [
-            'initialize',
+            'grabpl',
         ],
         'environment': {
             'GRAFANA_TEST_DB': 'mysql',
@@ -734,8 +734,7 @@ def redis_integration_tests_step():
         'name': 'redis-integration-tests',
         'image': build_image,
         'depends_on': [
-            'test-backend',
-            'test-frontend',
+            'grabpl',
         ],
         'environment': {
             'REDIS_URL': 'redis://redis:6379/0',
@@ -751,8 +750,7 @@ def memcached_integration_tests_step():
         'name': 'memcached-integration-tests',
         'image': build_image,
         'depends_on': [
-            'test-backend',
-            'test-frontend',
+            'grabpl',
         ],
         'environment': {
             'MEMCACHED_HOSTS': 'memcached:11211',
@@ -939,7 +937,7 @@ def get_windows_steps(edition, ver_mode, is_downstream=False):
         else:
             committish = '$$env:DRONE_COMMIT'
         # For enterprise, we have to clone both OSS and enterprise and merge the latter into the former
-        download_grabpl_cmds = [
+        download_grabpl_step_cmds = [
             '$$ProgressPreference = "SilentlyContinue"',
             'Invoke-WebRequest https://grafana-downloads.storage.googleapis.com/grafana-build-pipeline/v{}/windows/grabpl.exe -OutFile grabpl.exe'.format(grabpl_version),
         ]
@@ -957,7 +955,7 @@ def get_windows_steps(edition, ver_mode, is_downstream=False):
             'environment': {
                 'GITHUB_TOKEN': from_secret(github_token),
             },
-            'commands': download_grabpl_cmds + clone_cmds,
+            'commands': download_grabpl_step_cmds + clone_cmds,
         })
         steps[1]['depends_on'] = [
             'clone',