Updates to CI_CONFIG_PATH and CI_PROJECT_CONFIG_PATH variables

What does this MR do?

The existing Pipeline variable CI_CONFIG_PATH is same as the new Project variable CI_PROJECT_CONFIG_PATH introduced in #246802 (closed)

Now, CI_CONFIG_PATH is a Pipeline variable, and we support only Project variables in include section (required for evaluation of group level compliance pipeline configuration).

To prevent duplication of variables and to continue the support for referencing Project's config path in Compliance pipeline configuration include section, this MR adds the following changes:

1. Move CI_CONFIG_PATH as a Project variable (so we can use it in the include section)
2. Deprecate support for CI_PROJECT_CONFIG_PATH to avoid duplication of variables that have the same behavior. The variable will be removed in 14.0: #322807 (closed)

Mentions #321334 (closed)

Screenshots (strongly suggested)

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
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

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