Port over EE pipeline functionality to CE

What does this MR do?

This MR brings over ee pipeline functionality into ce. So ce will function as ee unlicensed. ce will now have the ability to visual multi-project pipelines and trigger them once the backend portion is done which you can see here !17251 (merged)

• Ports over all components, mixins and stores located in ee/app/assets/javascripts/pipelines to the corresponding ce directory.
• Updates any incorrect imports due to the port.
• Ports over existing ee specs related to pipelines and removes those corresponding directories

Related issue #31573 (closed)

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• 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

Closes #31573 (closed)