Introduce feature flag for cancel pipelines on delete

What does this MR do?

This introduced a feature flag for this issue surrounding pipeline deletion (for more context see the issue):

https://gitlab.com/gitlab-org/gitlab/-/issues/331891

The functionality is not complete and is not meant to be enabled yet.

This touches the major areas to be controlled by the flag.

1. Cancel on delete
2. Move consumption calculation sync (TODO: before enabling, update portion and email notification, need to be moved async)

MR where I introduce new services for the TODO's:

!65595 (diffs)

Screenshots or Screencasts (strongly suggested)

Does this MR meet the acceptance criteria?

Conformity

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• I have self-reviewed this MR per code review guidelines.
• This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
• I have followed the style guides.
• This change is backwards compatible across updates, or this does not apply.

Availability and Testing

• I have added/updated tests following the Testing Guide, or it's not needed. (Consider all test levels. See the Test Planning Process.)
• [-] I have tested this MR in all supported browsers, or it's not needed.
• [-] I have informed the Infrastructure department of a default or new setting change per definition of done, or it's not needed.

Security

Does this MR contain changes to processing or storing of credentials or tokens, authorization and authentication methods or other items described in the security review guidelines? If not, then delete this Security section.

• [-] Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• [-] Security reports checked/validated by a reviewer from the AppSec team