Introducing the GitLab CI/CD Catalog Beta

What this post added

Introduces the GitLab CI/CD Catalog (Beta) as a centralized hub for discovering and sharing reusable CI/CD components. Details the process for users to discover and include components in their `.gitlab-ci.yml` files. Outlines a six-step process for developers to create and publish their own CI/CD components, including project setup, component creation with input parameters using the `spec` keyword, documentation, testing, preparing a release job with semantic versioning, and publishing via Git tags.