25875-Add-Webex-Teams-project-integration-service

What does this MR do?

This merge request adds Webex Teams as a new project service, which allows submitting GitLab events as notifications to this service. Webex Teams is a collaboration tool, which also offers a free tiers.

It is functionality, implementation and documentation wise similar to the Unify Circuit project service.

Screenshots

Example for GitLab notifications in Webex Teams client:

Example for configuration of incoming webhoock in Webex Teams App Hub:

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

Closes #25875 (closed)