Implement workflow:rules:auto_cancel for CI

What does this MR do and why?

With workflow:rules:auto_cancel, users will be able to control their CI config's behaviors depending on some conditions (rules).

In this change, besides workflow:rules:auto_cancel:on_new_commit, workflow:rules:auto_cancel:on_job_failure is also implemented. However, since the workflow:auto_cancel:on_job_failure syntax is not used, it is not documented.

This change is behind the existing feature flag ci_workflow_auto_cancel_on_new_commit (#434676 (closed)).

Issue: #436467 (closed)

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Screenshots or screen recordings

Enable the FF:

Feature.enable(:ci_workflow_auto_cancel_on_new_commit)

Example config;

workflow:
  auto_cancel:
    on_new_commit: interruptible
  rules:
    - if: $CI_COMMIT_REF_PROTECTED == 'true'
      auto_cancel:
        on_new_commit: none
    - when: always                  # Run the pipeline in other cases

test1:
  script: sleep 10
  interruptible: false

test2:
  script: sleep 10
  interruptible: true

In a non-protected branch

Create a pipeline;

Send another commit and see the previous pipeline;

In a protected branch

Create a pipeline;

Send another commit and see the previous pipeline;