WIP: Create or update release

What does this MR do?

If defined in gitlab-ci.yaml this MR creates a Release entry. It will use the parsed config stored by !19550 (closed) and:

• create a Release or overwrite it if it exists
• and read the text file described in release:description and populate the Release description with this
• attach the assets defined in release:assets

Proposed steps

• Hook into BuildSuccessWorker and reload config from Ci::Build.ci_builds_metadata
• read changelog or other passed file
• create or update release entry
• attach artifacts as assets

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability 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 #26013 (closed)