[ci] add job switcher (#12922)

substrate/.gitlab-ci.yml

@@ -81,8 +81,14 @@ default:
     paths:
       - artifacts/
 
+.job-switcher:
+  before_script:
+    - if echo "$CI_DISABLED_JOBS" | grep -xF "$CI_JOB_NAME"; then echo "The job has been cancelled in CI settings"; exit 0; fi
+
 .kubernetes-env:
   image:                           "${CI_IMAGE}"
+  before_script:
+    - !reference [.job-switcher, before_script]
   tags:
     - kubernetes-parity-build
 
@@ -95,6 +101,7 @@ default:
 
 .pipeline-stopper-vars:
   script:
+    - !reference [.job-switcher, before_script]
     - echo "Collecting env variables for the cancel-pipeline job"
     - echo "FAILED_JOB_URL=${CI_JOB_URL}" > pipeline-stopper.env
     - echo "FAILED_JOB_NAME=${CI_JOB_NAME}" >> pipeline-stopper.env
@@ -110,6 +117,7 @@ default:
   before_script:
     # TODO: remove unset invocation when we'll be free from 'ENV RUSTC_WRAPPER=sccache' & sccache itself in all images
     - unset RUSTC_WRAPPER
+    - !reference [.job-switcher, before_script]
     - !reference [.rust-info-script, script]
     - !reference [.rusty-cachier, before_script]
     - !reference [.pipeline-stopper-vars, script]
@@ -300,7 +308,6 @@ rusty-cachier-notify:
     PR_NUM:                        "${PR_NUM}"
   trigger:
     project:                       "parity/infrastructure/ci_cd/pipeline-stopper"
-    branch:                        "as-improve"
 
 remove-cancel-pipeline-message:
   stage: .post