Update Gitlab Docs for CI/CD YAML with Top-level keys and their keywords found in config_options

Update the Gitlab docs for CI/CD Yaml reference with Top-level keys and their keywords found in config_options

Reference Issue

Top-level keys found in config_options

Reference MR

Add schema validations and guardrails for config_options (JSONB) column in build_metadata table

CICD Doc link

• https://docs.gitlab.com/development/cicd/
• https://docs.gitlab.com/ci/yaml/